fs/ceph/mds_client.c

   1 #include "ceph_debug.h"
   2
   3 #include <linux/wait.h>
   4 #include <linux/slab.h>
   5 #include <linux/sched.h>
   6
   7 #include "mds_client.h"
   8 #include "mon_client.h"
   9 #include "super.h"
  10 #include "messenger.h"
  11 #include "decode.h"
  12 #include "auth.h"
  13 #include "pagelist.h"
  14
  15 /*
  16  * A cluster of MDS (metadata server) daemons is responsible for
  17  * managing the file system namespace (the directory hierarchy and
  18  * inodes) and for coordinating shared access to storage.  Metadata is
  19  * partitioning hierarchically across a number of servers, and that
  20  * partition varies over time as the cluster adjusts the distribution
  21  * in order to balance load.
  22  *
  23  * The MDS client is primarily responsible to managing synchronous
  24  * metadata requests for operations like open, unlink, and so forth.
  25  * If there is a MDS failure, we find out about it when we (possibly
  26  * request and) receive a new MDS map, and can resubmit affected
  27  * requests.
  28  *
  29  * For the most part, though, we take advantage of a lossless
  30  * communications channel to the MDS, and do not need to worry about
  31  * timing out or resubmitting requests.
  32  *
  33  * We maintain a stateful "session" with each MDS we interact with.
  34  * Within each session, we sent periodic heartbeat messages to ensure
  35  * any capabilities or leases we have been issues remain valid.  If
  36  * the session times out and goes stale, our leases and capabilities
  37  * are no longer valid.
  38  */
  39
  40 static void __wake_requests(struct ceph_mds_client *mdsc,
  41                             struct list_head *head);
  42
  43 static const struct ceph_connection_operations mds_con_ops;
  44
  45
  46 /*
  47  * mds reply parsing
  48  */
  49
  50 /*
  51  * parse individual inode info
  52  */
  53 static int parse_reply_info_in(void **p, void *end,
  54                                struct ceph_mds_reply_info_in *info)
  55 {
  56         int err = -EIO;
  57
  58         info->in = *p;
  59         *p += sizeof(struct ceph_mds_reply_inode) +
  60                 sizeof(*info->in->fragtree.splits) *
  61                 le32_to_cpu(info->in->fragtree.nsplits);
  62
  63         ceph_decode_32_safe(p, end, info->symlink_len, bad);
  64         ceph_decode_need(p, end, info->symlink_len, bad);
  65         info->symlink = *p;
  66         *p += info->symlink_len;
  67
  68         ceph_decode_32_safe(p, end, info->xattr_len, bad);
  69         ceph_decode_need(p, end, info->xattr_len, bad);
  70         info->xattr_data = *p;
  71         *p += info->xattr_len;
  72         return 0;
  73 bad:
  74         return err;
  75 }
  76
  77 /*
  78  * parse a normal reply, which may contain a (dir+)dentry and/or a
  79  * target inode.
  80  */
  81 static int parse_reply_info_trace(void **p, void *end,
  82                                   struct ceph_mds_reply_info_parsed *info)
  83 {
  84         int err;
  85
  86         if (info->head->is_dentry) {
  87                 err = parse_reply_info_in(p, end, &info->diri);
  88                 if (err < 0)
  89                         goto out_bad;
  90
  91                 if (unlikely(*p + sizeof(*info->dirfrag) > end))
  92                         goto bad;
  93                 info->dirfrag = *p;
  94                 *p += sizeof(*info->dirfrag) +
  95                         sizeof(u32)*le32_to_cpu(info->dirfrag->ndist);
  96                 if (unlikely(*p > end))
  97                         goto bad;
  98
  99                 ceph_decode_32_safe(p, end, info->dname_len, bad);
 100                 ceph_decode_need(p, end, info->dname_len, bad);
 101                 info->dname = *p;
 102                 *p += info->dname_len;
 103                 info->dlease = *p;
 104                 *p += sizeof(*info->dlease);
 105         }
 106
 107         if (info->head->is_target) {
 108                 err = parse_reply_info_in(p, end, &info->targeti);
 109                 if (err < 0)
 110                         goto out_bad;
 111         }
 112
 113         if (unlikely(*p != end))
 114                 goto bad;
 115         return 0;
 116
 117 bad:
 118         err = -EIO;
 119 out_bad:
 120         pr_err("problem parsing mds trace %d\n", err);
 121         return err;
 122 }
 123
 124 /*
 125  * parse readdir results
 126  */
 127 static int parse_reply_info_dir(void **p, void *end,
 128                                 struct ceph_mds_reply_info_parsed *info)
 129 {
 130         u32 num, i = 0;
 131         int err;
 132
 133         info->dir_dir = *p;
 134         if (*p + sizeof(*info->dir_dir) > end)
 135                 goto bad;
 136         *p += sizeof(*info->dir_dir) +
 137                 sizeof(u32)*le32_to_cpu(info->dir_dir->ndist);
 138         if (*p > end)
 139                 goto bad;
 140
 141         ceph_decode_need(p, end, sizeof(num) + 2, bad);
 142         num = ceph_decode_32(p);
 143         info->dir_end = ceph_decode_8(p);
 144         info->dir_complete = ceph_decode_8(p);
 145         if (num == 0)
 146                 goto done;
 147
 148         /* alloc large array */
 149         info->dir_nr = num;
 150         info->dir_in = kcalloc(num, sizeof(*info->dir_in) +
 151                                sizeof(*info->dir_dname) +
 152                                sizeof(*info->dir_dname_len) +
 153                                sizeof(*info->dir_dlease),
 154                                GFP_NOFS);
 155         if (info->dir_in == NULL) {
 156                 err = -ENOMEM;
 157                 goto out_bad;
 158         }
 159         info->dir_dname = (void *)(info->dir_in + num);
 160         info->dir_dname_len = (void *)(info->dir_dname + num);
 161         info->dir_dlease = (void *)(info->dir_dname_len + num);
 162
 163         while (num) {
 164                 /* dentry */
 165                 ceph_decode_need(p, end, sizeof(u32)*2, bad);
 166                 info->dir_dname_len[i] = ceph_decode_32(p);
 167                 ceph_decode_need(p, end, info->dir_dname_len[i], bad);
 168                 info->dir_dname[i] = *p;
 169                 *p += info->dir_dname_len[i];
 170                 dout("parsed dir dname '%.*s'\n", info->dir_dname_len[i],
 171                      info->dir_dname[i]);
 172                 info->dir_dlease[i] = *p;
 173                 *p += sizeof(struct ceph_mds_reply_lease);
 174
 175                 /* inode */
 176                 err = parse_reply_info_in(p, end, &info->dir_in[i]);
 177                 if (err < 0)
 178                         goto out_bad;
 179                 i++;
 180                 num--;
 181         }
 182
 183 done:
 184         if (*p != end)
 185                 goto bad;
 186         return 0;
 187
 188 bad:
 189         err = -EIO;
 190 out_bad:
 191         pr_err("problem parsing dir contents %d\n", err);
 192         return err;
 193 }
 194
 195 /*
 196  * parse entire mds reply
 197  */
 198 static int parse_reply_info(struct ceph_msg *msg,
 199                             struct ceph_mds_reply_info_parsed *info)
 200 {
 201         void *p, *end;
 202         u32 len;
 203         int err;
 204
 205         info->head = msg->front.iov_base;
 206         p = msg->front.iov_base + sizeof(struct ceph_mds_reply_head);
 207         end = p + msg->front.iov_len - sizeof(struct ceph_mds_reply_head);
 208
 209         /* trace */
 210         ceph_decode_32_safe(&p, end, len, bad);
 211         if (len > 0) {
 212                 err = parse_reply_info_trace(&p, p+len, info);
 213                 if (err < 0)
 214                         goto out_bad;
 215         }
 216
 217         /* dir content */
 218         ceph_decode_32_safe(&p, end, len, bad);
 219         if (len > 0) {
 220                 err = parse_reply_info_dir(&p, p+len, info);
 221                 if (err < 0)
 222                         goto out_bad;
 223         }
 224
 225         /* snap blob */
 226         ceph_decode_32_safe(&p, end, len, bad);
 227         info->snapblob_len = len;
 228         info->snapblob = p;
 229         p += len;
 230
 231         if (p != end)
 232                 goto bad;
 233         return 0;
 234
 235 bad:
 236         err = -EIO;
 237 out_bad:
 238         pr_err("mds parse_reply err %d\n", err);
 239         return err;
 240 }
 241
 242 static void destroy_reply_info(struct ceph_mds_reply_info_parsed *info)
 243 {
 244         kfree(info->dir_in);
 245 }
 246
 247
 248 /*
 249  * sessions
 250  */
 251 static const char *session_state_name(int s)
 252 {
 253         switch (s) {
 254         case CEPH_MDS_SESSION_NEW: return "new";
 255         case CEPH_MDS_SESSION_OPENING: return "opening";
 256         case CEPH_MDS_SESSION_OPEN: return "open";
 257         case CEPH_MDS_SESSION_HUNG: return "hung";
 258         case CEPH_MDS_SESSION_CLOSING: return "closing";
 259         case CEPH_MDS_SESSION_RESTARTING: return "restarting";
 260         case CEPH_MDS_SESSION_RECONNECTING: return "reconnecting";
 261         default: return "???";
 262         }
 263 }
 264
 265 static struct ceph_mds_session *get_session(struct ceph_mds_session *s)
 266 {
 267         if (atomic_inc_not_zero(&s->s_ref)) {
 268                 dout("mdsc get_session %p %d -> %d\n", s,
 269                      atomic_read(&s->s_ref)-1, atomic_read(&s->s_ref));
 270                 return s;
 271         } else {
 272                 dout("mdsc get_session %p 0 -- FAIL", s);
 273                 return NULL;
 274         }
 275 }
 276
 277 void ceph_put_mds_session(struct ceph_mds_session *s)
 278 {
 279         dout("mdsc put_session %p %d -> %d\n", s,
 280              atomic_read(&s->s_ref), atomic_read(&s->s_ref)-1);
 281         if (atomic_dec_and_test(&s->s_ref)) {
 282                 if (s->s_authorizer)
 283                         s->s_mdsc->client->monc.auth->ops->destroy_authorizer(
 284                                 s->s_mdsc->client->monc.auth, s->s_authorizer);
 285                 kfree(s);
 286         }
 287 }
 288
 289 /*
 290  * called under mdsc->mutex
 291  */
 292 struct ceph_mds_session *__ceph_lookup_mds_session(struct ceph_mds_client *mdsc,
 293                                                    int mds)
 294 {
 295         struct ceph_mds_session *session;
 296
 297         if (mds >= mdsc->max_sessions || mdsc->sessions[mds] == NULL)
 298                 return NULL;
 299         session = mdsc->sessions[mds];
 300         dout("lookup_mds_session %p %d\n", session,
 301              atomic_read(&session->s_ref));
 302         get_session(session);
 303         return session;
 304 }
 305
 306 static bool __have_session(struct ceph_mds_client *mdsc, int mds)
 307 {
 308         if (mds >= mdsc->max_sessions)
 309                 return false;
 310         return mdsc->sessions[mds];
 311 }
 312
 313 static int __verify_registered_session(struct ceph_mds_client *mdsc,
 314                                        struct ceph_mds_session *s)
 315 {
 316         if (s->s_mds >= mdsc->max_sessions ||
 317             mdsc->sessions[s->s_mds] != s)
 318                 return -ENOENT;
 319         return 0;
 320 }
 321
 322 /*
 323  * create+register a new session for given mds.
 324  * called under mdsc->mutex.
 325  */
 326 static struct ceph_mds_session *register_session(struct ceph_mds_client *mdsc,
 327                                                  int mds)
 328 {
 329         struct ceph_mds_session *s;
 330
 331         s = kzalloc(sizeof(*s), GFP_NOFS);
 332         if (!s)
 333                 return ERR_PTR(-ENOMEM);
 334         s->s_mdsc = mdsc;
 335         s->s_mds = mds;
 336         s->s_state = CEPH_MDS_SESSION_NEW;
 337         s->s_ttl = 0;
 338         s->s_seq = 0;
 339         mutex_init(&s->s_mutex);
 340
 341         ceph_con_init(mdsc->client->msgr, &s->s_con);
 342         s->s_con.private = s;
 343         s->s_con.ops = &mds_con_ops;
 344         s->s_con.peer_name.type = CEPH_ENTITY_TYPE_MDS;
 345         s->s_con.peer_name.num = cpu_to_le64(mds);
 346
 347         spin_lock_init(&s->s_cap_lock);
 348         s->s_cap_gen = 0;
 349         s->s_cap_ttl = 0;
 350         s->s_renew_requested = 0;
 351         s->s_renew_seq = 0;
 352         INIT_LIST_HEAD(&s->s_caps);
 353         s->s_nr_caps = 0;
 354         s->s_trim_caps = 0;
 355         atomic_set(&s->s_ref, 1);
 356         INIT_LIST_HEAD(&s->s_waiting);
 357         INIT_LIST_HEAD(&s->s_unsafe);
 358         s->s_num_cap_releases = 0;
 359         s->s_cap_iterator = NULL;
 360         INIT_LIST_HEAD(&s->s_cap_releases);
 361         INIT_LIST_HEAD(&s->s_cap_releases_done);
 362         INIT_LIST_HEAD(&s->s_cap_flushing);
 363         INIT_LIST_HEAD(&s->s_cap_snaps_flushing);
 364
 365         dout("register_session mds%d\n", mds);
 366         if (mds >= mdsc->max_sessions) {
 367                 int newmax = 1 << get_count_order(mds+1);
 368                 struct ceph_mds_session **sa;
 369
 370                 dout("register_session realloc to %d\n", newmax);
 371                 sa = kcalloc(newmax, sizeof(void *), GFP_NOFS);
 372                 if (sa == NULL)
 373                         goto fail_realloc;
 374                 if (mdsc->sessions) {
 375                         memcpy(sa, mdsc->sessions,
 376                                mdsc->max_sessions * sizeof(void *));
 377                         kfree(mdsc->sessions);
 378                 }
 379                 mdsc->sessions = sa;
 380                 mdsc->max_sessions = newmax;
 381         }
 382         mdsc->sessions[mds] = s;
 383         atomic_inc(&s->s_ref);  /* one ref to sessions[], one to caller */
 384
 385         ceph_con_open(&s->s_con, ceph_mdsmap_get_addr(mdsc->mdsmap, mds));
 386
 387         return s;
 388
 389 fail_realloc:
 390         kfree(s);
 391         return ERR_PTR(-ENOMEM);
 392 }
 393
 394 /*
 395  * called under mdsc->mutex
 396  */
 397 static void __unregister_session(struct ceph_mds_client *mdsc,
 398                                struct ceph_mds_session *s)
 399 {
 400         dout("__unregister_session mds%d %p\n", s->s_mds, s);
 401         BUG_ON(mdsc->sessions[s->s_mds] != s);
 402         mdsc->sessions[s->s_mds] = NULL;
 403         ceph_con_close(&s->s_con);
 404         ceph_put_mds_session(s);
 405 }
 406
 407 /*
 408  * drop session refs in request.
 409  *
 410  * should be last request ref, or hold mdsc->mutex
 411  */
 412 static void put_request_session(struct ceph_mds_request *req)
 413 {
 414         if (req->r_session) {
 415                 ceph_put_mds_session(req->r_session);
 416                 req->r_session = NULL;
 417         }
 418 }
 419
 420 void ceph_mdsc_release_request(struct kref *kref)
 421 {
 422         struct ceph_mds_request *req = container_of(kref,
 423                                                     struct ceph_mds_request,
 424                                                     r_kref);
 425         if (req->r_request)
 426                 ceph_msg_put(req->r_request);
 427         if (req->r_reply) {
 428                 ceph_msg_put(req->r_reply);
 429                 destroy_reply_info(&req->r_reply_info);
 430         }
 431         if (req->r_inode) {
 432                 ceph_put_cap_refs(ceph_inode(req->r_inode),
 433                                   CEPH_CAP_PIN);
 434                 iput(req->r_inode);
 435         }
 436         if (req->r_locked_dir)
 437                 ceph_put_cap_refs(ceph_inode(req->r_locked_dir),
 438                                   CEPH_CAP_PIN);
 439         if (req->r_target_inode)
 440                 iput(req->r_target_inode);
 441         if (req->r_dentry)
 442                 dput(req->r_dentry);
 443         if (req->r_old_dentry) {
 444                 ceph_put_cap_refs(
 445                         ceph_inode(req->r_old_dentry->d_parent->d_inode),
 446                         CEPH_CAP_PIN);
 447                 dput(req->r_old_dentry);
 448         }
 449         kfree(req->r_path1);
 450         kfree(req->r_path2);
 451         put_request_session(req);
 452         ceph_unreserve_caps(&req->r_caps_reservation);
 453         kfree(req);
 454 }
 455
 456 /*
 457  * lookup session, bump ref if found.
 458  *
 459  * called under mdsc->mutex.
 460  */
 461 static struct ceph_mds_request *__lookup_request(struct ceph_mds_client *mdsc,
 462                                              u64 tid)
 463 {
 464         struct ceph_mds_request *req;
 465         struct rb_node *n = mdsc->request_tree.rb_node;
 466
 467         while (n) {
 468                 req = rb_entry(n, struct ceph_mds_request, r_node);
 469                 if (tid < req->r_tid)
 470                         n = n->rb_left;
 471                 else if (tid > req->r_tid)
 472                         n = n->rb_right;
 473                 else {
 474                         ceph_mdsc_get_request(req);
 475                         return req;
 476                 }
 477         }
 478         return NULL;
 479 }
 480
 481 static void __insert_request(struct ceph_mds_client *mdsc,
 482                              struct ceph_mds_request *new)
 483 {
 484         struct rb_node **p = &mdsc->request_tree.rb_node;
 485         struct rb_node *parent = NULL;
 486         struct ceph_mds_request *req = NULL;
 487
 488         while (*p) {
 489                 parent = *p;
 490                 req = rb_entry(parent, struct ceph_mds_request, r_node);
 491                 if (new->r_tid < req->r_tid)
 492                         p = &(*p)->rb_left;
 493                 else if (new->r_tid > req->r_tid)
 494                         p = &(*p)->rb_right;
 495                 else
 496                         BUG();
 497         }
 498
 499         rb_link_node(&new->r_node, parent, p);
 500         rb_insert_color(&new->r_node, &mdsc->request_tree);
 501 }
 502
 503 /*
 504  * Register an in-flight request, and assign a tid.  Link to directory
 505  * are modifying (if any).
 506  *
 507  * Called under mdsc->mutex.
 508  */
 509 static void __register_request(struct ceph_mds_client *mdsc,
 510                                struct ceph_mds_request *req,
 511                                struct inode *dir)
 512 {
 513         req->r_tid = ++mdsc->last_tid;
 514         if (req->r_num_caps)
 515                 ceph_reserve_caps(&req->r_caps_reservation, req->r_num_caps);
 516         dout("__register_request %p tid %lld\n", req, req->r_tid);
 517         ceph_mdsc_get_request(req);
 518         __insert_request(mdsc, req);
 519
 520         if (dir) {
 521                 struct ceph_inode_info *ci = ceph_inode(dir);
 522
 523                 spin_lock(&ci->i_unsafe_lock);
 524                 req->r_unsafe_dir = dir;
 525                 list_add_tail(&req->r_unsafe_dir_item, &ci->i_unsafe_dirops);
 526                 spin_unlock(&ci->i_unsafe_lock);
 527         }
 528 }
 529
 530 static void __unregister_request(struct ceph_mds_client *mdsc,
 531                                  struct ceph_mds_request *req)
 532 {
 533         dout("__unregister_request %p tid %lld\n", req, req->r_tid);
 534         rb_erase(&req->r_node, &mdsc->request_tree);
 535         RB_CLEAR_NODE(&req->r_node);
 536
 537         if (req->r_unsafe_dir) {
 538                 struct ceph_inode_info *ci = ceph_inode(req->r_unsafe_dir);
 539
 540                 spin_lock(&ci->i_unsafe_lock);
 541                 list_del_init(&req->r_unsafe_dir_item);
 542                 spin_unlock(&ci->i_unsafe_lock);
 543         }
 544
 545         ceph_mdsc_put_request(req);
 546 }
 547
 548 /*
 549  * Choose mds to send request to next.  If there is a hint set in the
 550  * request (e.g., due to a prior forward hint from the mds), use that.
 551  * Otherwise, consult frag tree and/or caps to identify the
 552  * appropriate mds.  If all else fails, choose randomly.
 553  *
 554  * Called under mdsc->mutex.
 555  */
 556 static int __choose_mds(struct ceph_mds_client *mdsc,
 557                         struct ceph_mds_request *req)
 558 {
 559         struct inode *inode;
 560         struct ceph_inode_info *ci;
 561         struct ceph_cap *cap;
 562         int mode = req->r_direct_mode;
 563         int mds = -1;
 564         u32 hash = req->r_direct_hash;
 565         bool is_hash = req->r_direct_is_hash;
 566
 567         /*
 568          * is there a specific mds we should try?  ignore hint if we have
 569          * no session and the mds is not up (active or recovering).
 570          */
 571         if (req->r_resend_mds >= 0 &&
 572             (__have_session(mdsc, req->r_resend_mds) ||
 573              ceph_mdsmap_get_state(mdsc->mdsmap, req->r_resend_mds) > 0)) {
 574                 dout("choose_mds using resend_mds mds%d\n",
 575                      req->r_resend_mds);
 576                 return req->r_resend_mds;
 577         }
 578
 579         if (mode == USE_RANDOM_MDS)
 580                 goto random;
 581
 582         inode = NULL;
 583         if (req->r_inode) {
 584                 inode = req->r_inode;
 585         } else if (req->r_dentry) {
 586                 if (req->r_dentry->d_inode) {
 587                         inode = req->r_dentry->d_inode;
 588                 } else {
 589                         inode = req->r_dentry->d_parent->d_inode;
 590                         hash = req->r_dentry->d_name.hash;
 591                         is_hash = true;
 592                 }
 593         }
 594         dout("__choose_mds %p is_hash=%d (%d) mode %d\n", inode, (int)is_hash,
 595              (int)hash, mode);
 596         if (!inode)
 597                 goto random;
 598         ci = ceph_inode(inode);
 599
 600         if (is_hash && S_ISDIR(inode->i_mode)) {
 601                 struct ceph_inode_frag frag;
 602                 int found;
 603
 604                 ceph_choose_frag(ci, hash, &frag, &found);
 605                 if (found) {
 606                         if (mode == USE_ANY_MDS && frag.ndist > 0) {
 607                                 u8 r;
 608
 609                                 /* choose a random replica */
 610                                 get_random_bytes(&r, 1);
 611                                 r %= frag.ndist;
 612                                 mds = frag.dist[r];
 613                                 dout("choose_mds %p %llx.%llx "
 614                                      "frag %u mds%d (%d/%d)\n",
 615                                      inode, ceph_vinop(inode),
 616                                      frag.frag, frag.mds,
 617                                      (int)r, frag.ndist);
 618                                 return mds;
 619                         }
 620
 621                         /* since this file/dir wasn't known to be
 622                          * replicated, then we want to look for the
 623                          * authoritative mds. */
 624                         mode = USE_AUTH_MDS;
 625                         if (frag.mds >= 0) {
 626                                 /* choose auth mds */
 627                                 mds = frag.mds;
 628                                 dout("choose_mds %p %llx.%llx "
 629                                      "frag %u mds%d (auth)\n",
 630                                      inode, ceph_vinop(inode), frag.frag, mds);
 631                                 return mds;
 632                         }
 633                 }
 634         }
 635
 636         spin_lock(&inode->i_lock);
 637         cap = NULL;
 638         if (mode == USE_AUTH_MDS)
 639                 cap = ci->i_auth_cap;
 640         if (!cap && !RB_EMPTY_ROOT(&ci->i_caps))
 641                 cap = rb_entry(rb_first(&ci->i_caps), struct ceph_cap, ci_node);
 642         if (!cap) {
 643                 spin_unlock(&inode->i_lock);
 644                 goto random;
 645         }
 646         mds = cap->session->s_mds;
 647         dout("choose_mds %p %llx.%llx mds%d (%scap %p)\n",
 648              inode, ceph_vinop(inode), mds,
 649              cap == ci->i_auth_cap ? "auth " : "", cap);
 650         spin_unlock(&inode->i_lock);
 651         return mds;
 652
 653 random:
 654         mds = ceph_mdsmap_get_random_mds(mdsc->mdsmap);
 655         dout("choose_mds chose random mds%d\n", mds);
 656         return mds;
 657 }
 658
 659
 660 /*
 661  * session messages
 662  */
 663 static struct ceph_msg *create_session_msg(u32 op, u64 seq)
 664 {
 665         struct ceph_msg *msg;
 666         struct ceph_mds_session_head *h;
 667
 668         msg = ceph_msg_new(CEPH_MSG_CLIENT_SESSION, sizeof(*h), GFP_NOFS);
 669         if (!msg) {
 670                 pr_err("create_session_msg ENOMEM creating msg\n");
 671                 return NULL;
 672         }
 673         h = msg->front.iov_base;
 674         h->op = cpu_to_le32(op);
 675         h->seq = cpu_to_le64(seq);
 676         return msg;
 677 }
 678
 679 /*
 680  * send session open request.
 681  *
 682  * called under mdsc->mutex
 683  */
 684 static int __open_session(struct ceph_mds_client *mdsc,
 685                           struct ceph_mds_session *session)
 686 {
 687         struct ceph_msg *msg;
 688         int mstate;
 689         int mds = session->s_mds;
 690
 691         /* wait for mds to go active? */
 692         mstate = ceph_mdsmap_get_state(mdsc->mdsmap, mds);
 693         dout("open_session to mds%d (%s)\n", mds,
 694              ceph_mds_state_name(mstate));
 695         session->s_state = CEPH_MDS_SESSION_OPENING;
 696         session->s_renew_requested = jiffies;
 697
 698         /* send connect message */
 699         msg = create_session_msg(CEPH_SESSION_REQUEST_OPEN, session->s_seq);
 700         if (!msg)
 701                 return -ENOMEM;
 702         ceph_con_send(&session->s_con, msg);
 703         return 0;
 704 }
 705
 706 /*
 707  * session caps
 708  */
 709
 710 /*
 711  * Free preallocated cap messages assigned to this session
 712  */
 713 static void cleanup_cap_releases(struct ceph_mds_session *session)
 714 {
 715         struct ceph_msg *msg;
 716
 717         spin_lock(&session->s_cap_lock);
 718         while (!list_empty(&session->s_cap_releases)) {
 719                 msg = list_first_entry(&session->s_cap_releases,
 720                                        struct ceph_msg, list_head);
 721                 list_del_init(&msg->list_head);
 722                 ceph_msg_put(msg);
 723         }
 724         while (!list_empty(&session->s_cap_releases_done)) {
 725                 msg = list_first_entry(&session->s_cap_releases_done,
 726                                        struct ceph_msg, list_head);
 727                 list_del_init(&msg->list_head);
 728                 ceph_msg_put(msg);
 729         }
 730         spin_unlock(&session->s_cap_lock);
 731 }
 732
 733 /*
 734  * Helper to safely iterate over all caps associated with a session, with
 735  * special care taken to handle a racing __ceph_remove_cap().
 736  *
 737  * Caller must hold session s_mutex.
 738  */
 739 static int iterate_session_caps(struct ceph_mds_session *session,
 740                                  int (*cb)(struct inode *, struct ceph_cap *,
 741                                             void *), void *arg)
 742 {
 743         struct list_head *p;
 744         struct ceph_cap *cap;
 745         struct inode *inode, *last_inode = NULL;
 746         struct ceph_cap *old_cap = NULL;
 747         int ret;
 748
 749         dout("iterate_session_caps %p mds%d\n", session, session->s_mds);
 750         spin_lock(&session->s_cap_lock);
 751         p = session->s_caps.next;
 752         while (p != &session->s_caps) {
 753                 cap = list_entry(p, struct ceph_cap, session_caps);
 754                 inode = igrab(&cap->ci->vfs_inode);
 755                 if (!inode) {
 756                         p = p->next;
 757                         continue;
 758                 }
 759                 session->s_cap_iterator = cap;
 760                 spin_unlock(&session->s_cap_lock);
 761
 762                 if (last_inode) {
 763                         iput(last_inode);
 764                         last_inode = NULL;
 765                 }
 766                 if (old_cap) {
 767                         ceph_put_cap(old_cap);
 768                         old_cap = NULL;
 769                 }
 770
 771                 ret = cb(inode, cap, arg);
 772                 last_inode = inode;
 773
 774                 spin_lock(&session->s_cap_lock);
 775                 p = p->next;
 776                 if (cap->ci == NULL) {
 777                         dout("iterate_session_caps  finishing cap %p removal\n",
 778                              cap);
 779                         BUG_ON(cap->session != session);
 780                         list_del_init(&cap->session_caps);
 781                         session->s_nr_caps--;
 782                         cap->session = NULL;
 783                         old_cap = cap;  /* put_cap it w/o locks held */
 784                 }
 785                 if (ret < 0)
 786                         goto out;
 787         }
 788         ret = 0;
 789 out:
 790         session->s_cap_iterator = NULL;
 791         spin_unlock(&session->s_cap_lock);
 792
 793         if (last_inode)
 794                 iput(last_inode);
 795         if (old_cap)
 796                 ceph_put_cap(old_cap);
 797
 798         return ret;
 799 }
 800
 801 static int remove_session_caps_cb(struct inode *inode, struct ceph_cap *cap,
 802                                   void *arg)
 803 {
 804         struct ceph_inode_info *ci = ceph_inode(inode);
 805         int drop = 0;
 806
 807         dout("removing cap %p, ci is %p, inode is %p\n",
 808              cap, ci, &ci->vfs_inode);
 809         spin_lock(&inode->i_lock);
 810         __ceph_remove_cap(cap);
 811         if (!__ceph_is_any_real_caps(ci)) {
 812                 struct ceph_mds_client *mdsc =
 813                         &ceph_sb_to_client(inode->i_sb)->mdsc;
 814
 815                 spin_lock(&mdsc->cap_dirty_lock);
 816                 if (!list_empty(&ci->i_dirty_item)) {
 817                         pr_info(" dropping dirty %s state for %p %lld\n",
 818                                 ceph_cap_string(ci->i_dirty_caps),
 819                                 inode, ceph_ino(inode));
 820                         ci->i_dirty_caps = 0;
 821                         list_del_init(&ci->i_dirty_item);
 822                         drop = 1;
 823                 }
 824                 if (!list_empty(&ci->i_flushing_item)) {
 825                         pr_info(" dropping dirty+flushing %s state for %p %lld\n",
 826                                 ceph_cap_string(ci->i_flushing_caps),
 827                                 inode, ceph_ino(inode));
 828                         ci->i_flushing_caps = 0;
 829                         list_del_init(&ci->i_flushing_item);
 830                         mdsc->num_cap_flushing--;
 831                         drop = 1;
 832                 }
 833                 if (drop && ci->i_wrbuffer_ref) {
 834                         pr_info(" dropping dirty data for %p %lld\n",
 835                                 inode, ceph_ino(inode));
 836                         ci->i_wrbuffer_ref = 0;
 837                         ci->i_wrbuffer_ref_head = 0;
 838                         drop++;
 839                 }
 840                 spin_unlock(&mdsc->cap_dirty_lock);
 841         }
 842         spin_unlock(&inode->i_lock);
 843         while (drop--)
 844                 iput(inode);
 845         return 0;
 846 }
 847
 848 /*
 849  * caller must hold session s_mutex
 850  */
 851 static void remove_session_caps(struct ceph_mds_session *session)
 852 {
 853         dout("remove_session_caps on %p\n", session);
 854         iterate_session_caps(session, remove_session_caps_cb, NULL);
 855         BUG_ON(session->s_nr_caps > 0);
 856         BUG_ON(!list_empty(&session->s_cap_flushing));
 857         cleanup_cap_releases(session);
 858 }
 859
 860 /*
 861  * wake up any threads waiting on this session's caps.  if the cap is
 862  * old (didn't get renewed on the client reconnect), remove it now.
 863  *
 864  * caller must hold s_mutex.
 865  */
 866 static int wake_up_session_cb(struct inode *inode, struct ceph_cap *cap,
 867                               void *arg)
 868 {
 869         struct ceph_inode_info *ci = ceph_inode(inode);
 870
 871         wake_up(&ci->i_cap_wq);
 872         if (arg) {
 873                 spin_lock(&inode->i_lock);
 874                 ci->i_wanted_max_size = 0;
 875                 ci->i_requested_max_size = 0;
 876                 spin_unlock(&inode->i_lock);
 877         }
 878         return 0;
 879 }
 880
 881 static void wake_up_session_caps(struct ceph_mds_session *session,
 882                                  int reconnect)
 883 {
 884         dout("wake_up_session_caps %p mds%d\n", session, session->s_mds);
 885         iterate_session_caps(session, wake_up_session_cb,
 886                              (void *)(unsigned long)reconnect);
 887 }
 888
 889 /*
 890  * Send periodic message to MDS renewing all currently held caps.  The
 891  * ack will reset the expiration for all caps from this session.
 892  *
 893  * caller holds s_mutex
 894  */
 895 static int send_renew_caps(struct ceph_mds_client *mdsc,
 896                            struct ceph_mds_session *session)
 897 {
 898         struct ceph_msg *msg;
 899         int state;
 900
 901         if (time_after_eq(jiffies, session->s_cap_ttl) &&
 902             time_after_eq(session->s_cap_ttl, session->s_renew_requested))
 903                 pr_info("mds%d caps stale\n", session->s_mds);
 904         session->s_renew_requested = jiffies;
 905
 906         /* do not try to renew caps until a recovering mds has reconnected
 907          * with its clients. */
 908         state = ceph_mdsmap_get_state(mdsc->mdsmap, session->s_mds);
 909         if (state < CEPH_MDS_STATE_RECONNECT) {
 910                 dout("send_renew_caps ignoring mds%d (%s)\n",
 911                      session->s_mds, ceph_mds_state_name(state));
 912                 return 0;
 913         }
 914
 915         dout("send_renew_caps to mds%d (%s)\n", session->s_mds,
 916                 ceph_mds_state_name(state));
 917         msg = create_session_msg(CEPH_SESSION_REQUEST_RENEWCAPS,
 918                                  ++session->s_renew_seq);
 919         if (!msg)
 920                 return -ENOMEM;
 921         ceph_con_send(&session->s_con, msg);
 922         return 0;
 923 }
 924
 925 /*
 926  * Note new cap ttl, and any transition from stale -> not stale (fresh?).
 927  *
 928  * Called under session->s_mutex
 929  */
 930 static void renewed_caps(struct ceph_mds_client *mdsc,
 931                          struct ceph_mds_session *session, int is_renew)
 932 {
 933         int was_stale;
 934         int wake = 0;
 935
 936         spin_lock(&session->s_cap_lock);
 937         was_stale = is_renew && (session->s_cap_ttl == 0 ||
 938                                  time_after_eq(jiffies, session->s_cap_ttl));
 939
 940         session->s_cap_ttl = session->s_renew_requested +
 941                 mdsc->mdsmap->m_session_timeout*HZ;
 942
 943         if (was_stale) {
 944                 if (time_before(jiffies, session->s_cap_ttl)) {
 945                         pr_info("mds%d caps renewed\n", session->s_mds);
 946                         wake = 1;
 947                 } else {
 948                         pr_info("mds%d caps still stale\n", session->s_mds);
 949                 }
 950         }
 951         dout("renewed_caps mds%d ttl now %lu, was %s, now %s\n",
 952              session->s_mds, session->s_cap_ttl, was_stale ? "stale" : "fresh",
 953              time_before(jiffies, session->s_cap_ttl) ? "stale" : "fresh");
 954         spin_unlock(&session->s_cap_lock);
 955
 956         if (wake)
 957                 wake_up_session_caps(session, 0);
 958 }
 959
 960 /*
 961  * send a session close request
 962  */
 963 static int request_close_session(struct ceph_mds_client *mdsc,
 964                                  struct ceph_mds_session *session)
 965 {
 966         struct ceph_msg *msg;
 967
 968         dout("request_close_session mds%d state %s seq %lld\n",
 969              session->s_mds, session_state_name(session->s_state),
 970              session->s_seq);
 971         msg = create_session_msg(CEPH_SESSION_REQUEST_CLOSE, session->s_seq);
 972         if (!msg)
 973                 return -ENOMEM;
 974         ceph_con_send(&session->s_con, msg);
 975         return 0;
 976 }
 977
 978 /*
 979  * Called with s_mutex held.
 980  */
 981 static int __close_session(struct ceph_mds_client *mdsc,
 982                          struct ceph_mds_session *session)
 983 {
 984         if (session->s_state >= CEPH_MDS_SESSION_CLOSING)
 985                 return 0;
 986         session->s_state = CEPH_MDS_SESSION_CLOSING;
 987         return request_close_session(mdsc, session);
 988 }
 989
 990 /*
 991  * Trim old(er) caps.
 992  *
 993  * Because we can't cache an inode without one or more caps, we do
 994  * this indirectly: if a cap is unused, we prune its aliases, at which
 995  * point the inode will hopefully get dropped to.
 996  *
 997  * Yes, this is a bit sloppy.  Our only real goal here is to respond to
 998  * memory pressure from the MDS, though, so it needn't be perfect.
 999  */
1000 static int trim_caps_cb(struct inode *inode, struct ceph_cap *cap, void *arg)
1001 {
1002         struct ceph_mds_session *session = arg;
1003         struct ceph_inode_info *ci = ceph_inode(inode);
1004         int used, oissued, mine;
1005
1006         if (session->s_trim_caps <= 0)
1007                 return -1;
1008
1009         spin_lock(&inode->i_lock);
1010         mine = cap->issued | cap->implemented;
1011         used = __ceph_caps_used(ci);
1012         oissued = __ceph_caps_issued_other(ci, cap);
1013
1014         dout("trim_caps_cb %p cap %p mine %s oissued %s used %s\n",
1015              inode, cap, ceph_cap_string(mine), ceph_cap_string(oissued),
1016              ceph_cap_string(used));
1017         if (ci->i_dirty_caps)
1018                 goto out;   /* dirty caps */
1019         if ((used & ~oissued) & mine)
1020                 goto out;   /* we need these caps */
1021
1022         session->s_trim_caps--;
1023         if (oissued) {
1024                 /* we aren't the only cap.. just remove us */
1025                 __ceph_remove_cap(cap);
1026         } else {
1027                 /* try to drop referring dentries */
1028                 spin_unlock(&inode->i_lock);
1029                 d_prune_aliases(inode);
1030                 dout("trim_caps_cb %p cap %p  pruned, count now %d\n",
1031                      inode, cap, atomic_read(&inode->i_count));
1032                 return 0;
1033         }
1034
1035 out:
1036         spin_unlock(&inode->i_lock);
1037         return 0;
1038 }
1039
1040 /*
1041  * Trim session cap count down to some max number.
1042  */
1043 static int trim_caps(struct ceph_mds_client *mdsc,
1044                      struct ceph_mds_session *session,
1045                      int max_caps)
1046 {
1047         int trim_caps = session->s_nr_caps - max_caps;
1048
1049         dout("trim_caps mds%d start: %d / %d, trim %d\n",
1050              session->s_mds, session->s_nr_caps, max_caps, trim_caps);
1051         if (trim_caps > 0) {
1052                 session->s_trim_caps = trim_caps;
1053                 iterate_session_caps(session, trim_caps_cb, session);
1054                 dout("trim_caps mds%d done: %d / %d, trimmed %d\n",
1055                      session->s_mds, session->s_nr_caps, max_caps,
1056                         trim_caps - session->s_trim_caps);
1057                 session->s_trim_caps = 0;
1058         }
1059         return 0;
1060 }
1061
1062 /*
1063  * Allocate cap_release messages.  If there is a partially full message
1064  * in the queue, try to allocate enough to cover it's remainder, so that
1065  * we can send it immediately.
1066  *
1067  * Called under s_mutex.
1068  */
1069 int ceph_add_cap_releases(struct ceph_mds_client *mdsc,
1070                           struct ceph_mds_session *session,
1071                           int extra)
1072 {
1073         struct ceph_msg *msg;
1074         struct ceph_mds_cap_release *head;
1075         int err = -ENOMEM;
1076
1077         if (extra < 0)
1078                 extra = mdsc->client->mount_args->cap_release_safety;
1079
1080         spin_lock(&session->s_cap_lock);
1081
1082         if (!list_empty(&session->s_cap_releases)) {
1083                 msg = list_first_entry(&session->s_cap_releases,
1084                                        struct ceph_msg,
1085                                  list_head);
1086                 head = msg->front.iov_base;
1087                 extra += CEPH_CAPS_PER_RELEASE - le32_to_cpu(head->num);
1088         }
1089
1090         while (session->s_num_cap_releases < session->s_nr_caps + extra) {
1091                 spin_unlock(&session->s_cap_lock);
1092                 msg = ceph_msg_new(CEPH_MSG_CLIENT_CAPRELEASE, PAGE_CACHE_SIZE,
1093                                    GFP_NOFS);
1094                 if (!msg)
1095                         goto out_unlocked;
1096                 dout("add_cap_releases %p msg %p now %d\n", session, msg,
1097                      (int)msg->front.iov_len);
1098                 head = msg->front.iov_base;
1099                 head->num = cpu_to_le32(0);
1100                 msg->front.iov_len = sizeof(*head);
1101                 spin_lock(&session->s_cap_lock);
1102                 list_add(&msg->list_head, &session->s_cap_releases);
1103                 session->s_num_cap_releases += CEPH_CAPS_PER_RELEASE;
1104         }
1105
1106         if (!list_empty(&session->s_cap_releases)) {
1107                 msg = list_first_entry(&session->s_cap_releases,
1108                                        struct ceph_msg,
1109                                        list_head);
1110                 head = msg->front.iov_base;
1111                 if (head->num) {
1112                         dout(" queueing non-full %p (%d)\n", msg,
1113                              le32_to_cpu(head->num));
1114                         list_move_tail(&msg->list_head,
1115                                       &session->s_cap_releases_done);
1116                         session->s_num_cap_releases -=
1117                                 CEPH_CAPS_PER_RELEASE - le32_to_cpu(head->num);
1118                 }
1119         }
1120         err = 0;
1121         spin_unlock(&session->s_cap_lock);
1122 out_unlocked:
1123         return err;
1124 }
1125
1126 /*
1127  * flush all dirty inode data to disk.
1128  *
1129  * returns true if we've flushed through want_flush_seq
1130  */
1131 static int check_cap_flush(struct ceph_mds_client *mdsc, u64 want_flush_seq)
1132 {
1133         int mds, ret = 1;
1134
1135         dout("check_cap_flush want %lld\n", want_flush_seq);
1136         mutex_lock(&mdsc->mutex);
1137         for (mds = 0; ret && mds < mdsc->max_sessions; mds++) {
1138                 struct ceph_mds_session *session = mdsc->sessions[mds];
1139
1140                 if (!session)
1141                         continue;
1142                 get_session(session);
1143                 mutex_unlock(&mdsc->mutex);
1144
1145                 mutex_lock(&session->s_mutex);
1146                 if (!list_empty(&session->s_cap_flushing)) {
1147                         struct ceph_inode_info *ci =
1148                                 list_entry(session->s_cap_flushing.next,
1149                                            struct ceph_inode_info,
1150                                            i_flushing_item);
1151                         struct inode *inode = &ci->vfs_inode;
1152
1153                         spin_lock(&inode->i_lock);
1154                         if (ci->i_cap_flush_seq <= want_flush_seq) {
1155                                 dout("check_cap_flush still flushing %p "
1156                                      "seq %lld <= %lld to mds%d\n", inode,
1157                                      ci->i_cap_flush_seq, want_flush_seq,
1158                                      session->s_mds);
1159                                 ret = 0;
1160                         }
1161                         spin_unlock(&inode->i_lock);
1162                 }
1163                 mutex_unlock(&session->s_mutex);
1164                 ceph_put_mds_session(session);
1165
1166                 if (!ret)
1167                         return ret;
1168                 mutex_lock(&mdsc->mutex);
1169         }
1170
1171         mutex_unlock(&mdsc->mutex);
1172         dout("check_cap_flush ok, flushed thru %lld\n", want_flush_seq);
1173         return ret;
1174 }
1175
1176 /*
1177  * called under s_mutex
1178  */
1179 void ceph_send_cap_releases(struct ceph_mds_client *mdsc,
1180                             struct ceph_mds_session *session)
1181 {
1182         struct ceph_msg *msg;
1183
1184         dout("send_cap_releases mds%d\n", session->s_mds);
1185         spin_lock(&session->s_cap_lock);
1186         while (!list_empty(&session->s_cap_releases_done)) {
1187                 msg = list_first_entry(&session->s_cap_releases_done,
1188                                  struct ceph_msg, list_head);
1189                 list_del_init(&msg->list_head);
1190                 spin_unlock(&session->s_cap_lock);
1191                 msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
1192                 dout("send_cap_releases mds%d %p\n", session->s_mds, msg);
1193                 ceph_con_send(&session->s_con, msg);
1194                 spin_lock(&session->s_cap_lock);
1195         }
1196         spin_unlock(&session->s_cap_lock);
1197 }
1198
1199 static void discard_cap_releases(struct ceph_mds_client *mdsc,
1200                                  struct ceph_mds_session *session)
1201 {
1202         struct ceph_msg *msg;
1203         struct ceph_mds_cap_release *head;
1204         unsigned num;
1205
1206         dout("discard_cap_releases mds%d\n", session->s_mds);
1207         spin_lock(&session->s_cap_lock);
1208
1209         /* zero out the in-progress message */
1210         msg = list_first_entry(&session->s_cap_releases,
1211                                struct ceph_msg, list_head);
1212         head = msg->front.iov_base;
1213         num = le32_to_cpu(head->num);
1214         dout("discard_cap_releases mds%d %p %u\n", session->s_mds, msg, num);
1215         head->num = cpu_to_le32(0);
1216         session->s_num_cap_releases += num;
1217
1218         /* requeue completed messages */
1219         while (!list_empty(&session->s_cap_releases_done)) {
1220                 msg = list_first_entry(&session->s_cap_releases_done,
1221                                  struct ceph_msg, list_head);
1222                 list_del_init(&msg->list_head);
1223
1224                 head = msg->front.iov_base;
1225                 num = le32_to_cpu(head->num);
1226                 dout("discard_cap_releases mds%d %p %u\n", session->s_mds, msg,
1227                      num);
1228                 session->s_num_cap_releases += num;
1229                 head->num = cpu_to_le32(0);
1230                 msg->front.iov_len = sizeof(*head);
1231                 list_add(&msg->list_head, &session->s_cap_releases);
1232         }
1233
1234         spin_unlock(&session->s_cap_lock);
1235 }
1236
1237 /*
1238  * requests
1239  */
1240
1241 /*
1242  * Create an mds request.
1243  */
1244 struct ceph_mds_request *
1245 ceph_mdsc_create_request(struct ceph_mds_client *mdsc, int op, int mode)
1246 {
1247         struct ceph_mds_request *req = kzalloc(sizeof(*req), GFP_NOFS);
1248
1249         if (!req)
1250                 return ERR_PTR(-ENOMEM);
1251
1252         mutex_init(&req->r_fill_mutex);
1253         req->r_started = jiffies;
1254         req->r_resend_mds = -1;
1255         INIT_LIST_HEAD(&req->r_unsafe_dir_item);
1256         req->r_fmode = -1;
1257         kref_init(&req->r_kref);
1258         INIT_LIST_HEAD(&req->r_wait);
1259         init_completion(&req->r_completion);
1260         init_completion(&req->r_safe_completion);
1261         INIT_LIST_HEAD(&req->r_unsafe_item);
1262
1263         req->r_op = op;
1264         req->r_direct_mode = mode;
1265         return req;
1266 }
1267
1268 /*
1269  * return oldest (lowest) request, tid in request tree, 0 if none.
1270  *
1271  * called under mdsc->mutex.
1272  */
1273 static struct ceph_mds_request *__get_oldest_req(struct ceph_mds_client *mdsc)
1274 {
1275         if (RB_EMPTY_ROOT(&mdsc->request_tree))
1276                 return NULL;
1277         return rb_entry(rb_first(&mdsc->request_tree),
1278                         struct ceph_mds_request, r_node);
1279 }
1280
1281 static u64 __get_oldest_tid(struct ceph_mds_client *mdsc)
1282 {
1283         struct ceph_mds_request *req = __get_oldest_req(mdsc);
1284
1285         if (req)
1286                 return req->r_tid;
1287         return 0;
1288 }
1289
1290 /*
1291  * Build a dentry's path.  Allocate on heap; caller must kfree.  Based
1292  * on build_path_from_dentry in fs/cifs/dir.c.
1293  *
1294  * If @stop_on_nosnap, generate path relative to the first non-snapped
1295  * inode.
1296  *
1297  * Encode hidden .snap dirs as a double /, i.e.
1298  *   foo/.snap/bar -> foo//bar
1299  */
1300 char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *base,
1301                            int stop_on_nosnap)
1302 {
1303         struct dentry *temp;
1304         char *path;
1305         int len, pos;
1306
1307         if (dentry == NULL)
1308                 return ERR_PTR(-EINVAL);
1309
1310 retry:
1311         len = 0;
1312         for (temp = dentry; !IS_ROOT(temp);) {
1313                 struct inode *inode = temp->d_inode;
1314                 if (inode && ceph_snap(inode) == CEPH_SNAPDIR)
1315                         len++;  /* slash only */
1316                 else if (stop_on_nosnap && inode &&
1317                          ceph_snap(inode) == CEPH_NOSNAP)
1318                         break;
1319                 else
1320                         len += 1 + temp->d_name.len;
1321                 temp = temp->d_parent;
1322                 if (temp == NULL) {
1323                         pr_err("build_path corrupt dentry %p\n", dentry);
1324                         return ERR_PTR(-EINVAL);
1325                 }
1326         }
1327         if (len)
1328                 len--;  /* no leading '/' */
1329
1330         path = kmalloc(len+1, GFP_NOFS);
1331         if (path == NULL)
1332                 return ERR_PTR(-ENOMEM);
1333         pos = len;
1334         path[pos] = 0;  /* trailing null */
1335         for (temp = dentry; !IS_ROOT(temp) && pos != 0; ) {
1336                 struct inode *inode = temp->d_inode;
1337
1338                 if (inode && ceph_snap(inode) == CEPH_SNAPDIR) {
1339                         dout("build_path path+%d: %p SNAPDIR\n",
1340                              pos, temp);
1341                 } else if (stop_on_nosnap && inode &&
1342                            ceph_snap(inode) == CEPH_NOSNAP) {
1343                         break;
1344                 } else {
1345                         pos -= temp->d_name.len;
1346                         if (pos < 0)
1347                                 break;
1348                         strncpy(path + pos, temp->d_name.name,
1349                                 temp->d_name.len);
1350                 }
1351                 if (pos)
1352                         path[--pos] = '/';
1353                 temp = temp->d_parent;
1354                 if (temp == NULL) {
1355                         pr_err("build_path corrupt dentry\n");
1356                         kfree(path);
1357                         return ERR_PTR(-EINVAL);
1358                 }
1359         }
1360         if (pos != 0) {
1361                 pr_err("build_path did not end path lookup where "
1362                        "expected, namelen is %d, pos is %d\n", len, pos);
1363                 /* presumably this is only possible if racing with a
1364                    rename of one of the parent directories (we can not
1365                    lock the dentries above us to prevent this, but
1366                    retrying should be harmless) */
1367                 kfree(path);
1368                 goto retry;
1369         }
1370
1371         *base = ceph_ino(temp->d_inode);
1372         *plen = len;
1373         dout("build_path on %p %d built %llx '%.*s'\n",
1374              dentry, atomic_read(&dentry->d_count), *base, len, path);
1375         return path;
1376 }
1377
1378 static int build_dentry_path(struct dentry *dentry,
1379                              const char **ppath, int *ppathlen, u64 *pino,
1380                              int *pfreepath)
1381 {
1382         char *path;
1383
1384         if (ceph_snap(dentry->d_parent->d_inode) == CEPH_NOSNAP) {
1385                 *pino = ceph_ino(dentry->d_parent->d_inode);
1386                 *ppath = dentry->d_name.name;
1387                 *ppathlen = dentry->d_name.len;
1388                 return 0;
1389         }
1390         path = ceph_mdsc_build_path(dentry, ppathlen, pino, 1);
1391         if (IS_ERR(path))
1392                 return PTR_ERR(path);
1393         *ppath = path;
1394         *pfreepath = 1;
1395         return 0;
1396 }
1397
1398 static int build_inode_path(struct inode *inode,
1399                             const char **ppath, int *ppathlen, u64 *pino,
1400                             int *pfreepath)
1401 {
1402         struct dentry *dentry;
1403         char *path;
1404
1405         if (ceph_snap(inode) == CEPH_NOSNAP) {
1406                 *pino = ceph_ino(inode);
1407                 *ppathlen = 0;
1408                 return 0;
1409         }
1410         dentry = d_find_alias(inode);
1411         path = ceph_mdsc_build_path(dentry, ppathlen, pino, 1);
1412         dput(dentry);
1413         if (IS_ERR(path))
1414                 return PTR_ERR(path);
1415         *ppath = path;
1416         *pfreepath = 1;
1417         return 0;
1418 }
1419
1420 /*
1421  * request arguments may be specified via an inode *, a dentry *, or
1422  * an explicit ino+path.
1423  */
1424 static int set_request_path_attr(struct inode *rinode, struct dentry *rdentry,
1425                                   const char *rpath, u64 rino,
1426                                   const char **ppath, int *pathlen,
1427                                   u64 *ino, int *freepath)
1428 {
1429         int r = 0;
1430
1431         if (rinode) {
1432                 r = build_inode_path(rinode, ppath, pathlen, ino, freepath);
1433                 dout(" inode %p %llx.%llx\n", rinode, ceph_ino(rinode),
1434                      ceph_snap(rinode));
1435         } else if (rdentry) {
1436                 r = build_dentry_path(rdentry, ppath, pathlen, ino, freepath);
1437                 dout(" dentry %p %llx/%.*s\n", rdentry, *ino, *pathlen,
1438                      *ppath);
1439         } else if (rpath) {
1440                 *ino = rino;
1441                 *ppath = rpath;
1442                 *pathlen = strlen(rpath);
1443                 dout(" path %.*s\n", *pathlen, rpath);
1444         }
1445
1446         return r;
1447 }
1448
1449 /*
1450  * called under mdsc->mutex
1451  */
1452 static struct ceph_msg *create_request_message(struct ceph_mds_client *mdsc,
1453                                                struct ceph_mds_request *req,
1454                                                int mds)
1455 {
1456         struct ceph_msg *msg;
1457         struct ceph_mds_request_head *head;
1458         const char *path1 = NULL;
1459         const char *path2 = NULL;
1460         u64 ino1 = 0, ino2 = 0;
1461         int pathlen1 = 0, pathlen2 = 0;
1462         int freepath1 = 0, freepath2 = 0;
1463         int len;
1464         u16 releases;
1465         void *p, *end;
1466         int ret;
1467
1468         ret = set_request_path_attr(req->r_inode, req->r_dentry,
1469                               req->r_path1, req->r_ino1.ino,
1470                               &path1, &pathlen1, &ino1, &freepath1);
1471         if (ret < 0) {
1472                 msg = ERR_PTR(ret);
1473                 goto out;
1474         }
1475
1476         ret = set_request_path_attr(NULL, req->r_old_dentry,
1477                               req->r_path2, req->r_ino2.ino,
1478                               &path2, &pathlen2, &ino2, &freepath2);
1479         if (ret < 0) {
1480                 msg = ERR_PTR(ret);
1481                 goto out_free1;
1482         }
1483
1484         len = sizeof(*head) +
1485                 pathlen1 + pathlen2 + 2*(1 + sizeof(u32) + sizeof(u64));
1486
1487         /* calculate (max) length for cap releases */
1488         len += sizeof(struct ceph_mds_request_release) *
1489                 (!!req->r_inode_drop + !!req->r_dentry_drop +
1490                  !!req->r_old_inode_drop + !!req->r_old_dentry_drop);
1491         if (req->r_dentry_drop)
1492                 len += req->r_dentry->d_name.len;
1493         if (req->r_old_dentry_drop)
1494                 len += req->r_old_dentry->d_name.len;
1495
1496         msg = ceph_msg_new(CEPH_MSG_CLIENT_REQUEST, len, GFP_NOFS);
1497         if (!msg) {
1498                 msg = ERR_PTR(-ENOMEM);
1499                 goto out_free2;
1500         }
1501
1502         msg->hdr.tid = cpu_to_le64(req->r_tid);
1503
1504         head = msg->front.iov_base;
1505         p = msg->front.iov_base + sizeof(*head);
1506         end = msg->front.iov_base + msg->front.iov_len;
1507
1508         head->mdsmap_epoch = cpu_to_le32(mdsc->mdsmap->m_epoch);
1509         head->op = cpu_to_le32(req->r_op);
1510         head->caller_uid = cpu_to_le32(current_fsuid());
1511         head->caller_gid = cpu_to_le32(current_fsgid());
1512         head->args = req->r_args;
1513
1514         ceph_encode_filepath(&p, end, ino1, path1);
1515         ceph_encode_filepath(&p, end, ino2, path2);
1516
1517         /* cap releases */
1518         releases = 0;
1519         if (req->r_inode_drop)
1520                 releases += ceph_encode_inode_release(&p,
1521                       req->r_inode ? req->r_inode : req->r_dentry->d_inode,
1522                       mds, req->r_inode_drop, req->r_inode_unless, 0);
1523         if (req->r_dentry_drop)
1524                 releases += ceph_encode_dentry_release(&p, req->r_dentry,
1525                        mds, req->r_dentry_drop, req->r_dentry_unless);
1526         if (req->r_old_dentry_drop)
1527                 releases += ceph_encode_dentry_release(&p, req->r_old_dentry,
1528                        mds, req->r_old_dentry_drop, req->r_old_dentry_unless);
1529         if (req->r_old_inode_drop)
1530                 releases += ceph_encode_inode_release(&p,
1531                       req->r_old_dentry->d_inode,
1532                       mds, req->r_old_inode_drop, req->r_old_inode_unless, 0);
1533         head->num_releases = cpu_to_le16(releases);
1534
1535         BUG_ON(p > end);
1536         msg->front.iov_len = p - msg->front.iov_base;
1537         msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
1538
1539         msg->pages = req->r_pages;
1540         msg->nr_pages = req->r_num_pages;
1541         msg->hdr.data_len = cpu_to_le32(req->r_data_len);
1542         msg->hdr.data_off = cpu_to_le16(0);
1543
1544 out_free2:
1545         if (freepath2)
1546                 kfree((char *)path2);
1547 out_free1:
1548         if (freepath1)
1549                 kfree((char *)path1);
1550 out:
1551         return msg;
1552 }
1553
1554 /*
1555  * called under mdsc->mutex if error, under no mutex if
1556  * success.
1557  */
1558 static void complete_request(struct ceph_mds_client *mdsc,
1559                              struct ceph_mds_request *req)
1560 {
1561         if (req->r_callback)
1562                 req->r_callback(mdsc, req);
1563         else
1564                 complete(&req->r_completion);
1565 }
1566
1567 /*
1568  * called under mdsc->mutex
1569  */
1570 static int __prepare_send_request(struct ceph_mds_client *mdsc,
1571                                   struct ceph_mds_request *req,
1572                                   int mds)
1573 {
1574         struct ceph_mds_request_head *rhead;
1575         struct ceph_msg *msg;
1576         int flags = 0;
1577
1578         req->r_mds = mds;
1579         req->r_attempts++;
1580         dout("prepare_send_request %p tid %lld %s (attempt %d)\n", req,
1581              req->r_tid, ceph_mds_op_name(req->r_op), req->r_attempts);
1582
1583         if (req->r_got_unsafe) {
1584                 /*
1585                  * Replay.  Do not regenerate message (and rebuild
1586                  * paths, etc.); just use the original message.
1587                  * Rebuilding paths will break for renames because
1588                  * d_move mangles the src name.
1589                  */
1590                 msg = req->r_request;
1591                 rhead = msg->front.iov_base;
1592
1593                 flags = le32_to_cpu(rhead->flags);
1594                 flags |= CEPH_MDS_FLAG_REPLAY;
1595                 rhead->flags = cpu_to_le32(flags);
1596
1597                 if (req->r_target_inode)
1598                         rhead->ino = cpu_to_le64(ceph_ino(req->r_target_inode));
1599
1600                 rhead->num_retry = req->r_attempts - 1;
1601                 return 0;
1602         }
1603
1604         if (req->r_request) {
1605                 ceph_msg_put(req->r_request);
1606                 req->r_request = NULL;
1607         }
1608         msg = create_request_message(mdsc, req, mds);
1609         if (IS_ERR(msg)) {
1610                 req->r_err = PTR_ERR(msg);
1611                 complete_request(mdsc, req);
1612                 return PTR_ERR(msg);
1613         }
1614         req->r_request = msg;
1615
1616         rhead = msg->front.iov_base;
1617         rhead->oldest_client_tid = cpu_to_le64(__get_oldest_tid(mdsc));
1618         if (req->r_got_unsafe)
1619                 flags |= CEPH_MDS_FLAG_REPLAY;
1620         if (req->r_locked_dir)
1621                 flags |= CEPH_MDS_FLAG_WANT_DENTRY;
1622         rhead->flags = cpu_to_le32(flags);
1623         rhead->num_fwd = req->r_num_fwd;
1624         rhead->num_retry = req->r_attempts - 1;
1625         rhead->ino = 0;
1626
1627         dout(" r_locked_dir = %p\n", req->r_locked_dir);
1628         return 0;
1629 }
1630
1631 /*
1632  * send request, or put it on the appropriate wait list.
1633  */
1634 static int __do_request(struct ceph_mds_client *mdsc,
1635                         struct ceph_mds_request *req)
1636 {
1637         struct ceph_mds_session *session = NULL;
1638         int mds = -1;
1639         int err = -EAGAIN;
1640
1641         if (req->r_err || req->r_got_result)
1642                 goto out;
1643
1644         if (req->r_timeout &&
1645             time_after_eq(jiffies, req->r_started + req->r_timeout)) {
1646                 dout("do_request timed out\n");
1647                 err = -EIO;
1648                 goto finish;
1649         }
1650
1651         mds = __choose_mds(mdsc, req);
1652         if (mds < 0 ||
1653             ceph_mdsmap_get_state(mdsc->mdsmap, mds) < CEPH_MDS_STATE_ACTIVE) {
1654                 dout("do_request no mds or not active, waiting for map\n");
1655                 list_add(&req->r_wait, &mdsc->waiting_for_map);
1656                 goto out;
1657         }
1658
1659         /* get, open session */
1660         session = __ceph_lookup_mds_session(mdsc, mds);
1661         if (!session) {
1662                 session = register_session(mdsc, mds);
1663                 if (IS_ERR(session)) {
1664                         err = PTR_ERR(session);
1665                         goto finish;
1666                 }
1667         }
1668         dout("do_request mds%d session %p state %s\n", mds, session,
1669              session_state_name(session->s_state));
1670         if (session->s_state != CEPH_MDS_SESSION_OPEN &&
1671             session->s_state != CEPH_MDS_SESSION_HUNG) {
1672                 if (session->s_state == CEPH_MDS_SESSION_NEW ||
1673                     session->s_state == CEPH_MDS_SESSION_CLOSING)
1674                         __open_session(mdsc, session);
1675                 list_add(&req->r_wait, &session->s_waiting);
1676                 goto out_session;
1677         }
1678
1679         /* send request */
1680         req->r_session = get_session(session);
1681         req->r_resend_mds = -1;   /* forget any previous mds hint */
1682
1683         if (req->r_request_started == 0)   /* note request start time */
1684                 req->r_request_started = jiffies;
1685
1686         err = __prepare_send_request(mdsc, req, mds);
1687         if (!err) {
1688                 ceph_msg_get(req->r_request);
1689                 ceph_con_send(&session->s_con, req->r_request);
1690         }
1691
1692 out_session:
1693         ceph_put_mds_session(session);
1694 out:
1695         return err;
1696
1697 finish:
1698         req->r_err = err;
1699         complete_request(mdsc, req);
1700         goto out;
1701 }
1702
1703 /*
1704  * called under mdsc->mutex
1705  */
1706 static void __wake_requests(struct ceph_mds_client *mdsc,
1707                             struct list_head *head)
1708 {
1709         struct ceph_mds_request *req, *nreq;
1710
1711         list_for_each_entry_safe(req, nreq, head, r_wait) {
1712                 list_del_init(&req->r_wait);
1713                 __do_request(mdsc, req);
1714         }
1715 }
1716
1717 /*
1718  * Wake up threads with requests pending for @mds, so that they can
1719  * resubmit their requests to a possibly different mds.
1720  */
1721 static void kick_requests(struct ceph_mds_client *mdsc, int mds)
1722 {
1723         struct ceph_mds_request *req;
1724         struct rb_node *p;
1725
1726         dout("kick_requests mds%d\n", mds);
1727         for (p = rb_first(&mdsc->request_tree); p; p = rb_next(p)) {
1728                 req = rb_entry(p, struct ceph_mds_request, r_node);
1729                 if (req->r_got_unsafe)
1730                         continue;
1731                 if (req->r_session &&
1732                     req->r_session->s_mds == mds) {
1733                         dout(" kicking tid %llu\n", req->r_tid);
1734                         put_request_session(req);
1735                         __do_request(mdsc, req);
1736                 }
1737         }
1738 }
1739
1740 void ceph_mdsc_submit_request(struct ceph_mds_client *mdsc,
1741                               struct ceph_mds_request *req)
1742 {
1743         dout("submit_request on %p\n", req);
1744         mutex_lock(&mdsc->mutex);
1745         __register_request(mdsc, req, NULL);
1746         __do_request(mdsc, req);
1747         mutex_unlock(&mdsc->mutex);
1748 }
1749
1750 /*
1751  * Synchrously perform an mds request.  Take care of all of the
1752  * session setup, forwarding, retry details.
1753  */
1754 int ceph_mdsc_do_request(struct ceph_mds_client *mdsc,
1755                          struct inode *dir,
1756                          struct ceph_mds_request *req)
1757 {
1758         int err;
1759
1760         dout("do_request on %p\n", req);
1761
1762         /* take CAP_PIN refs for r_inode, r_locked_dir, r_old_dentry */
1763         if (req->r_inode)
1764                 ceph_get_cap_refs(ceph_inode(req->r_inode), CEPH_CAP_PIN);
1765         if (req->r_locked_dir)
1766                 ceph_get_cap_refs(ceph_inode(req->r_locked_dir), CEPH_CAP_PIN);
1767         if (req->r_old_dentry)
1768                 ceph_get_cap_refs(
1769                         ceph_inode(req->r_old_dentry->d_parent->d_inode),
1770                         CEPH_CAP_PIN);
1771
1772         /* issue */
1773         mutex_lock(&mdsc->mutex);
1774         __register_request(mdsc, req, dir);
1775         __do_request(mdsc, req);
1776
1777         if (req->r_err) {
1778                 err = req->r_err;
1779                 __unregister_request(mdsc, req);
1780                 dout("do_request early error %d\n", err);
1781                 goto out;
1782         }
1783
1784         /* wait */
1785         mutex_unlock(&mdsc->mutex);
1786         dout("do_request waiting\n");
1787         if (req->r_timeout) {
1788                 err = (long)wait_for_completion_killable_timeout(
1789                         &req->r_completion, req->r_timeout);
1790                 if (err == 0)
1791                         err = -EIO;
1792         } else {
1793                 err = wait_for_completion_killable(&req->r_completion);
1794         }
1795         dout("do_request waited, got %d\n", err);
1796         mutex_lock(&mdsc->mutex);
1797
1798         /* only abort if we didn't race with a real reply */
1799         if (req->r_got_result) {
1800                 err = le32_to_cpu(req->r_reply_info.head->result);
1801         } else if (err < 0) {
1802                 dout("aborted request %lld with %d\n", req->r_tid, err);
1803
1804                 /*
1805                  * ensure we aren't running concurrently with
1806                  * ceph_fill_trace or ceph_readdir_prepopulate, which
1807                  * rely on locks (dir mutex) held by our caller.
1808                  */
1809                 mutex_lock(&req->r_fill_mutex);
1810                 req->r_err = err;
1811                 req->r_aborted = true;
1812                 mutex_unlock(&req->r_fill_mutex);
1813
1814                 if (req->r_locked_dir &&
1815                     (req->r_op & CEPH_MDS_OP_WRITE))
1816                         ceph_invalidate_dir_request(req);
1817         } else {
1818                 err = req->r_err;
1819         }
1820
1821 out:
1822         mutex_unlock(&mdsc->mutex);
1823         dout("do_request %p done, result %d\n", req, err);
1824         return err;
1825 }
1826
1827 /*
1828  * Invalidate dir I_COMPLETE, dentry lease state on an aborted MDS
1829  * namespace request.
1830  */
1831 void ceph_invalidate_dir_request(struct ceph_mds_request *req)
1832 {
1833         struct inode *inode = req->r_locked_dir;
1834         struct ceph_inode_info *ci = ceph_inode(inode);
1835
1836         dout("invalidate_dir_request %p (I_COMPLETE, lease(s))\n", inode);
1837         spin_lock(&inode->i_lock);
1838         ci->i_ceph_flags &= ~CEPH_I_COMPLETE;
1839         ci->i_release_count++;
1840         spin_unlock(&inode->i_lock);
1841
1842         if (req->r_dentry)
1843                 ceph_invalidate_dentry_lease(req->r_dentry);
1844         if (req->r_old_dentry)
1845                 ceph_invalidate_dentry_lease(req->r_old_dentry);
1846 }
1847
1848 /*
1849  * Handle mds reply.
1850  *
1851  * We take the session mutex and parse and process the reply immediately.
1852  * This preserves the logical ordering of replies, capabilities, etc., sent
1853  * by the MDS as they are applied to our local cache.
1854  */
1855 static void handle_reply(struct ceph_mds_session *session, struct ceph_msg *msg)
1856 {
1857         struct ceph_mds_client *mdsc = session->s_mdsc;
1858         struct ceph_mds_request *req;
1859         struct ceph_mds_reply_head *head = msg->front.iov_base;
1860         struct ceph_mds_reply_info_parsed *rinfo;  /* parsed reply info */
1861         u64 tid;
1862         int err, result;
1863         int mds = session->s_mds;
1864
1865         if (msg->front.iov_len < sizeof(*head)) {
1866                 pr_err("mdsc_handle_reply got corrupt (short) reply\n");
1867                 ceph_msg_dump(msg);
1868                 return;
1869         }
1870
1871         /* get request, session */
1872         tid = le64_to_cpu(msg->hdr.tid);
1873         mutex_lock(&mdsc->mutex);
1874         req = __lookup_request(mdsc, tid);
1875         if (!req) {
1876                 dout("handle_reply on unknown tid %llu\n", tid);
1877                 mutex_unlock(&mdsc->mutex);
1878                 return;
1879         }
1880         dout("handle_reply %p\n", req);
1881
1882         /* correct session? */
1883         if (req->r_session != session) {
1884                 pr_err("mdsc_handle_reply got %llu on session mds%d"
1885                        " not mds%d\n", tid, session->s_mds,
1886                        req->r_session ? req->r_session->s_mds : -1);
1887                 mutex_unlock(&mdsc->mutex);
1888                 goto out;
1889         }
1890
1891         /* dup? */
1892         if ((req->r_got_unsafe && !head->safe) ||
1893             (req->r_got_safe && head->safe)) {
1894                 pr_warning("got a dup %s reply on %llu from mds%d\n",
1895                            head->safe ? "safe" : "unsafe", tid, mds);
1896                 mutex_unlock(&mdsc->mutex);
1897                 goto out;
1898         }
1899         if (req->r_got_safe && !head->safe) {
1900                 pr_warning("got unsafe after safe on %llu from mds%d\n",
1901                            tid, mds);
1902                 mutex_unlock(&mdsc->mutex);
1903                 goto out;
1904         }
1905
1906         result = le32_to_cpu(head->result);
1907
1908         /*
1909          * Tolerate 2 consecutive ESTALEs from the same mds.
1910          * FIXME: we should be looking at the cap migrate_seq.
1911          */
1912         if (result == -ESTALE) {
1913                 req->r_direct_mode = USE_AUTH_MDS;
1914                 req->r_num_stale++;
1915                 if (req->r_num_stale <= 2) {
1916                         __do_request(mdsc, req);
1917                         mutex_unlock(&mdsc->mutex);
1918                         goto out;
1919                 }
1920         } else {
1921                 req->r_num_stale = 0;
1922         }
1923
1924         if (head->safe) {
1925                 req->r_got_safe = true;
1926                 __unregister_request(mdsc, req);
1927                 complete(&req->r_safe_completion);
1928
1929                 if (req->r_got_unsafe) {
1930                         /*
1931                          * We already handled the unsafe response, now do the
1932                          * cleanup.  No need to examine the response; the MDS
1933                          * doesn't include any result info in the safe
1934                          * response.  And even if it did, there is nothing
1935                          * useful we could do with a revised return value.
1936                          */
1937                         dout("got safe reply %llu, mds%d\n", tid, mds);
1938                         list_del_init(&req->r_unsafe_item);
1939
1940                         /* last unsafe request during umount? */
1941                         if (mdsc->stopping && !__get_oldest_req(mdsc))
1942                                 complete(&mdsc->safe_umount_waiters);
1943                         mutex_unlock(&mdsc->mutex);
1944                         goto out;
1945                 }
1946         } else {
1947                 req->r_got_unsafe = true;
1948                 list_add_tail(&req->r_unsafe_item, &req->r_session->s_unsafe);
1949         }
1950
1951         dout("handle_reply tid %lld result %d\n", tid, result);
1952         rinfo = &req->r_reply_info;
1953         err = parse_reply_info(msg, rinfo);
1954         mutex_unlock(&mdsc->mutex);
1955
1956         mutex_lock(&session->s_mutex);
1957         if (err < 0) {
1958                 pr_err("mdsc_handle_reply got corrupt reply mds%d\n", mds);
1959                 ceph_msg_dump(msg);
1960                 goto out_err;
1961         }
1962
1963         /* snap trace */
1964         if (rinfo->snapblob_len) {
1965                 down_write(&mdsc->snap_rwsem);
1966                 ceph_update_snap_trace(mdsc, rinfo->snapblob,
1967                                rinfo->snapblob + rinfo->snapblob_len,
1968                                le32_to_cpu(head->op) == CEPH_MDS_OP_RMSNAP);
1969                 downgrade_write(&mdsc->snap_rwsem);
1970         } else {
1971                 down_read(&mdsc->snap_rwsem);
1972         }
1973
1974         /* insert trace into our cache */
1975         mutex_lock(&req->r_fill_mutex);
1976         err = ceph_fill_trace(mdsc->client->sb, req, req->r_session);
1977         if (err == 0) {
1978                 if (result == 0 && rinfo->dir_nr)
1979                         ceph_readdir_prepopulate(req, req->r_session);
1980                 ceph_unreserve_caps(&req->r_caps_reservation);
1981         }
1982         mutex_unlock(&req->r_fill_mutex);
1983
1984         up_read(&mdsc->snap_rwsem);
1985 out_err:
1986         mutex_lock(&mdsc->mutex);
1987         if (!req->r_aborted) {
1988                 if (err) {
1989                         req->r_err = err;
1990                 } else {
1991                         req->r_reply = msg;
1992                         ceph_msg_get(msg);
1993                         req->r_got_result = true;
1994                 }
1995         } else {
1996                 dout("reply arrived after request %lld was aborted\n", tid);
1997         }
1998         mutex_unlock(&mdsc->mutex);
1999
2000         ceph_add_cap_releases(mdsc, req->r_session, -1);
2001         mutex_unlock(&session->s_mutex);
2002
2003         /* kick calling process */
2004         complete_request(mdsc, req);
2005 out:
2006         ceph_mdsc_put_request(req);
2007         return;
2008 }
2009
2010
2011
2012 /*
2013  * handle mds notification that our request has been forwarded.
2014  */
2015 static void handle_forward(struct ceph_mds_client *mdsc,
2016                            struct ceph_mds_session *session,
2017                            struct ceph_msg *msg)
2018 {
2019         struct ceph_mds_request *req;
2020         u64 tid = le64_to_cpu(msg->hdr.tid);
2021         u32 next_mds;
2022         u32 fwd_seq;
2023         int err = -EINVAL;
2024         void *p = msg->front.iov_base;
2025         void *end = p + msg->front.iov_len;
2026
2027         ceph_decode_need(&p, end, 2*sizeof(u32), bad);
2028         next_mds = ceph_decode_32(&p);
2029         fwd_seq = ceph_decode_32(&p);
2030
2031         mutex_lock(&mdsc->mutex);
2032         req = __lookup_request(mdsc, tid);
2033         if (!req) {
2034                 dout("forward tid %llu to mds%d - req dne\n", tid, next_mds);
2035                 goto out;  /* dup reply? */
2036         }
2037
2038         if (req->r_aborted) {
2039                 dout("forward tid %llu aborted, unregistering\n", tid);
2040                 __unregister_request(mdsc, req);
2041         } else if (fwd_seq <= req->r_num_fwd) {
2042                 dout("forward tid %llu to mds%d - old seq %d <= %d\n",
2043                      tid, next_mds, req->r_num_fwd, fwd_seq);
2044         } else {
2045                 /* resend. forward race not possible; mds would drop */
2046                 dout("forward tid %llu to mds%d (we resend)\n", tid, next_mds);
2047                 BUG_ON(req->r_err);
2048                 BUG_ON(req->r_got_result);
2049                 req->r_num_fwd = fwd_seq;
2050                 req->r_resend_mds = next_mds;
2051                 put_request_session(req);
2052                 __do_request(mdsc, req);
2053         }
2054         ceph_mdsc_put_request(req);
2055 out:
2056         mutex_unlock(&mdsc->mutex);
2057         return;
2058
2059 bad:
2060         pr_err("mdsc_handle_forward decode error err=%d\n", err);
2061 }
2062
2063 /*
2064  * handle a mds session control message
2065  */
2066 static void handle_session(struct ceph_mds_session *session,
2067                            struct ceph_msg *msg)
2068 {
2069         struct ceph_mds_client *mdsc = session->s_mdsc;
2070         u32 op;
2071         u64 seq;
2072         int mds = session->s_mds;
2073         struct ceph_mds_session_head *h = msg->front.iov_base;
2074         int wake = 0;
2075
2076         /* decode */
2077         if (msg->front.iov_len != sizeof(*h))
2078                 goto bad;
2079         op = le32_to_cpu(h->op);
2080         seq = le64_to_cpu(h->seq);
2081
2082         mutex_lock(&mdsc->mutex);
2083         if (op == CEPH_SESSION_CLOSE)
2084                 __unregister_session(mdsc, session);
2085         /* FIXME: this ttl calculation is generous */
2086         session->s_ttl = jiffies + HZ*mdsc->mdsmap->m_session_autoclose;
2087         mutex_unlock(&mdsc->mutex);
2088
2089         mutex_lock(&session->s_mutex);
2090
2091         dout("handle_session mds%d %s %p state %s seq %llu\n",
2092              mds, ceph_session_op_name(op), session,
2093              session_state_name(session->s_state), seq);
2094
2095         if (session->s_state == CEPH_MDS_SESSION_HUNG) {
2096                 session->s_state = CEPH_MDS_SESSION_OPEN;
2097                 pr_info("mds%d came back\n", session->s_mds);
2098         }
2099
2100         switch (op) {
2101         case CEPH_SESSION_OPEN:
2102                 if (session->s_state == CEPH_MDS_SESSION_RECONNECTING)
2103                         pr_info("mds%d reconnect success\n", session->s_mds);
2104                 session->s_state = CEPH_MDS_SESSION_OPEN;
2105                 renewed_caps(mdsc, session, 0);
2106                 wake = 1;
2107                 if (mdsc->stopping)
2108                         __close_session(mdsc, session);
2109                 break;
2110
2111         case CEPH_SESSION_RENEWCAPS:
2112                 if (session->s_renew_seq == seq)
2113                         renewed_caps(mdsc, session, 1);
2114                 break;
2115
2116         case CEPH_SESSION_CLOSE:
2117                 if (session->s_state == CEPH_MDS_SESSION_RECONNECTING)
2118                         pr_info("mds%d reconnect denied\n", session->s_mds);
2119                 remove_session_caps(session);
2120                 wake = 1; /* for good measure */
2121                 complete(&mdsc->session_close_waiters);
2122                 kick_requests(mdsc, mds);
2123                 break;
2124
2125         case CEPH_SESSION_STALE:
2126                 pr_info("mds%d caps went stale, renewing\n",
2127                         session->s_mds);
2128                 spin_lock(&session->s_cap_lock);
2129                 session->s_cap_gen++;
2130                 session->s_cap_ttl = 0;
2131                 spin_unlock(&session->s_cap_lock);
2132                 send_renew_caps(mdsc, session);
2133                 break;
2134
2135         case CEPH_SESSION_RECALL_STATE:
2136                 trim_caps(mdsc, session, le32_to_cpu(h->max_caps));
2137                 break;
2138
2139         default:
2140                 pr_err("mdsc_handle_session bad op %d mds%d\n", op, mds);
2141                 WARN_ON(1);
2142         }
2143
2144         mutex_unlock(&session->s_mutex);
2145         if (wake) {
2146                 mutex_lock(&mdsc->mutex);
2147                 __wake_requests(mdsc, &session->s_waiting);
2148                 mutex_unlock(&mdsc->mutex);
2149         }
2150         return;
2151
2152 bad:
2153         pr_err("mdsc_handle_session corrupt message mds%d len %d\n", mds,
2154                (int)msg->front.iov_len);
2155         ceph_msg_dump(msg);
2156         return;
2157 }
2158
2159
2160 /*
2161  * called under session->mutex.
2162  */
2163 static void replay_unsafe_requests(struct ceph_mds_client *mdsc,
2164                                    struct ceph_mds_session *session)
2165 {
2166         struct ceph_mds_request *req, *nreq;
2167         int err;
2168
2169         dout("replay_unsafe_requests mds%d\n", session->s_mds);
2170
2171         mutex_lock(&mdsc->mutex);
2172         list_for_each_entry_safe(req, nreq, &session->s_unsafe, r_unsafe_item) {
2173                 err = __prepare_send_request(mdsc, req, session->s_mds);
2174                 if (!err) {
2175                         ceph_msg_get(req->r_request);
2176                         ceph_con_send(&session->s_con, req->r_request);
2177                 }
2178         }
2179         mutex_unlock(&mdsc->mutex);
2180 }
2181
2182 /*
2183  * Encode information about a cap for a reconnect with the MDS.
2184  */
2185 static int encode_caps_cb(struct inode *inode, struct ceph_cap *cap,
2186                           void *arg)
2187 {
2188         struct ceph_mds_cap_reconnect rec;
2189         struct ceph_inode_info *ci;
2190         struct ceph_pagelist *pagelist = arg;
2191         char *path;
2192         int pathlen, err;
2193         u64 pathbase;
2194         struct dentry *dentry;
2195
2196         ci = cap->ci;
2197
2198         dout(" adding %p ino %llx.%llx cap %p %lld %s\n",
2199              inode, ceph_vinop(inode), cap, cap->cap_id,
2200              ceph_cap_string(cap->issued));
2201         err = ceph_pagelist_encode_64(pagelist, ceph_ino(inode));
2202         if (err)
2203                 return err;
2204
2205         dentry = d_find_alias(inode);
2206         if (dentry) {
2207                 path = ceph_mdsc_build_path(dentry, &pathlen, &pathbase, 0);
2208                 if (IS_ERR(path)) {
2209                         err = PTR_ERR(path);
2210                         BUG_ON(err);
2211                 }
2212         } else {
2213                 path = NULL;
2214                 pathlen = 0;
2215         }
2216         err = ceph_pagelist_encode_string(pagelist, path, pathlen);
2217         if (err)
2218                 goto out;
2219
2220         spin_lock(&inode->i_lock);
2221         cap->seq = 0;        /* reset cap seq */
2222         cap->issue_seq = 0;  /* and issue_seq */
2223         rec.cap_id = cpu_to_le64(cap->cap_id);
2224         rec.pathbase = cpu_to_le64(pathbase);
2225         rec.wanted = cpu_to_le32(__ceph_caps_wanted(ci));
2226         rec.issued = cpu_to_le32(cap->issued);
2227         rec.size = cpu_to_le64(inode->i_size);
2228         ceph_encode_timespec(&rec.mtime, &inode->i_mtime);
2229         ceph_encode_timespec(&rec.atime, &inode->i_atime);
2230         rec.snaprealm = cpu_to_le64(ci->i_snap_realm->ino);
2231         spin_unlock(&inode->i_lock);
2232
2233         err = ceph_pagelist_append(pagelist, &rec, sizeof(rec));
2234
2235 out:
2236         kfree(path);
2237         dput(dentry);
2238         return err;
2239 }
2240
2241
2242 /*
2243  * If an MDS fails and recovers, clients need to reconnect in order to
2244  * reestablish shared state.  This includes all caps issued through
2245  * this session _and_ the snap_realm hierarchy.  Because it's not
2246  * clear which snap realms the mds cares about, we send everything we
2247  * know about.. that ensures we'll then get any new info the
2248  * recovering MDS might have.
2249  *
2250  * This is a relatively heavyweight operation, but it's rare.
2251  *
2252  * called with mdsc->mutex held.
2253  */
2254 static void send_mds_reconnect(struct ceph_mds_client *mdsc,
2255                                struct ceph_mds_session *session)
2256 {
2257         struct ceph_msg *reply;
2258         struct rb_node *p;
2259         int mds = session->s_mds;
2260         int err = -ENOMEM;
2261         struct ceph_pagelist *pagelist;
2262
2263         pr_info("mds%d reconnect start\n", mds);
2264
2265         pagelist = kmalloc(sizeof(*pagelist), GFP_NOFS);
2266         if (!pagelist)
2267                 goto fail_nopagelist;
2268         ceph_pagelist_init(pagelist);
2269
2270         reply = ceph_msg_new(CEPH_MSG_CLIENT_RECONNECT, 0, GFP_NOFS);
2271         if (!reply)
2272                 goto fail_nomsg;
2273
2274         mutex_lock(&session->s_mutex);
2275         session->s_state = CEPH_MDS_SESSION_RECONNECTING;
2276         session->s_seq = 0;
2277
2278         ceph_con_open(&session->s_con,
2279                       ceph_mdsmap_get_addr(mdsc->mdsmap, mds));
2280
2281         /* replay unsafe requests */
2282         replay_unsafe_requests(mdsc, session);
2283
2284         down_read(&mdsc->snap_rwsem);
2285
2286         dout("session %p state %s\n", session,
2287              session_state_name(session->s_state));
2288
2289         /* drop old cap expires; we're about to reestablish that state */
2290         discard_cap_releases(mdsc, session);
2291
2292         /* traverse this session's caps */
2293         err = ceph_pagelist_encode_32(pagelist, session->s_nr_caps);
2294         if (err)
2295                 goto fail;
2296         err = iterate_session_caps(session, encode_caps_cb, pagelist);
2297         if (err < 0)
2298                 goto fail;
2299
2300         /*
2301          * snaprealms.  we provide mds with the ino, seq (version), and
2302          * parent for all of our realms.  If the mds has any newer info,
2303          * it will tell us.
2304          */
2305         for (p = rb_first(&mdsc->snap_realms); p; p = rb_next(p)) {
2306                 struct ceph_snap_realm *realm =
2307                         rb_entry(p, struct ceph_snap_realm, node);
2308                 struct ceph_mds_snaprealm_reconnect sr_rec;
2309
2310                 dout(" adding snap realm %llx seq %lld parent %llx\n",
2311                      realm->ino, realm->seq, realm->parent_ino);
2312                 sr_rec.ino = cpu_to_le64(realm->ino);
2313                 sr_rec.seq = cpu_to_le64(realm->seq);
2314                 sr_rec.parent = cpu_to_le64(realm->parent_ino);
2315                 err = ceph_pagelist_append(pagelist, &sr_rec, sizeof(sr_rec));
2316                 if (err)
2317                         goto fail;
2318         }
2319
2320         reply->pagelist = pagelist;
2321         reply->hdr.data_len = cpu_to_le32(pagelist->length);
2322         reply->nr_pages = calc_pages_for(0, pagelist->length);
2323         ceph_con_send(&session->s_con, reply);
2324
2325         mutex_unlock(&session->s_mutex);
2326
2327         mutex_lock(&mdsc->mutex);
2328         __wake_requests(mdsc, &session->s_waiting);
2329         mutex_unlock(&mdsc->mutex);
2330
2331         up_read(&mdsc->snap_rwsem);
2332         return;
2333
2334 fail:
2335         ceph_msg_put(reply);
2336         up_read(&mdsc->snap_rwsem);
2337         mutex_unlock(&session->s_mutex);
2338 fail_nomsg:
2339         ceph_pagelist_release(pagelist);
2340         kfree(pagelist);
2341 fail_nopagelist:
2342         pr_err("error %d preparing reconnect for mds%d\n", err, mds);
2343         return;
2344 }
2345
2346
2347 /*
2348  * compare old and new mdsmaps, kicking requests
2349  * and closing out old connections as necessary
2350  *
2351  * called under mdsc->mutex.
2352  */
2353 static void check_new_map(struct ceph_mds_client *mdsc,
2354                           struct ceph_mdsmap *newmap,
2355                           struct ceph_mdsmap *oldmap)
2356 {
2357         int i;
2358         int oldstate, newstate;
2359         struct ceph_mds_session *s;
2360
2361         dout("check_new_map new %u old %u\n",
2362              newmap->m_epoch, oldmap->m_epoch);
2363
2364         for (i = 0; i < oldmap->m_max_mds && i < mdsc->max_sessions; i++) {
2365                 if (mdsc->sessions[i] == NULL)
2366                         continue;
2367                 s = mdsc->sessions[i];
2368                 oldstate = ceph_mdsmap_get_state(oldmap, i);
2369                 newstate = ceph_mdsmap_get_state(newmap, i);
2370
2371                 dout("check_new_map mds%d state %s -> %s (session %s)\n",
2372                      i, ceph_mds_state_name(oldstate),
2373                      ceph_mds_state_name(newstate),
2374                      session_state_name(s->s_state));
2375
2376                 if (memcmp(ceph_mdsmap_get_addr(oldmap, i),
2377                            ceph_mdsmap_get_addr(newmap, i),
2378                            sizeof(struct ceph_entity_addr))) {
2379                         if (s->s_state == CEPH_MDS_SESSION_OPENING) {
2380                                 /* the session never opened, just close it
2381                                  * out now */
2382                                 __wake_requests(mdsc, &s->s_waiting);
2383                                 __unregister_session(mdsc, s);
2384                         } else {
2385                                 /* just close it */
2386                                 mutex_unlock(&mdsc->mutex);
2387                                 mutex_lock(&s->s_mutex);
2388                                 mutex_lock(&mdsc->mutex);
2389                                 ceph_con_close(&s->s_con);
2390                                 mutex_unlock(&s->s_mutex);
2391                                 s->s_state = CEPH_MDS_SESSION_RESTARTING;
2392                         }
2393
2394                         /* kick any requests waiting on the recovering mds */
2395                         kick_requests(mdsc, i);
2396                 } else if (oldstate == newstate) {
2397                         continue;  /* nothing new with this mds */
2398                 }
2399
2400                 /*
2401                  * send reconnect?
2402                  */
2403                 if (s->s_state == CEPH_MDS_SESSION_RESTARTING &&
2404                     newstate >= CEPH_MDS_STATE_RECONNECT) {
2405                         mutex_unlock(&mdsc->mutex);
2406                         send_mds_reconnect(mdsc, s);
2407                         mutex_lock(&mdsc->mutex);
2408                 }
2409
2410                 /*
2411                  * kick request on any mds that has gone active.
2412                  */
2413                 if (oldstate < CEPH_MDS_STATE_ACTIVE &&
2414                     newstate >= CEPH_MDS_STATE_ACTIVE) {
2415                         if (oldstate != CEPH_MDS_STATE_CREATING &&
2416                             oldstate != CEPH_MDS_STATE_STARTING)
2417                                 pr_info("mds%d recovery completed\n", s->s_mds);
2418                         kick_requests(mdsc, i);
2419                         ceph_kick_flushing_caps(mdsc, s);
2420                         wake_up_session_caps(s, 1);
2421                 }
2422         }
2423 }
2424
2425
2426
2427 /*
2428  * leases
2429  */
2430
2431 /*
2432  * caller must hold session s_mutex, dentry->d_lock
2433  */
2434 void __ceph_mdsc_drop_dentry_lease(struct dentry *dentry)
2435 {
2436         struct ceph_dentry_info *di = ceph_dentry(dentry);
2437
2438         ceph_put_mds_session(di->lease_session);
2439         di->lease_session = NULL;
2440 }
2441
2442 static void handle_lease(struct ceph_mds_client *mdsc,
2443                          struct ceph_mds_session *session,
2444                          struct ceph_msg *msg)
2445 {
2446         struct super_block *sb = mdsc->client->sb;
2447         struct inode *inode;
2448         struct ceph_inode_info *ci;
2449         struct dentry *parent, *dentry;
2450         struct ceph_dentry_info *di;
2451         int mds = session->s_mds;
2452         struct ceph_mds_lease *h = msg->front.iov_base;
2453         u32 seq;
2454         struct ceph_vino vino;
2455         int mask;
2456         struct qstr dname;
2457         int release = 0;
2458
2459         dout("handle_lease from mds%d\n", mds);
2460
2461         /* decode */
2462         if (msg->front.iov_len < sizeof(*h) + sizeof(u32))
2463                 goto bad;
2464         vino.ino = le64_to_cpu(h->ino);
2465         vino.snap = CEPH_NOSNAP;
2466         mask = le16_to_cpu(h->mask);
2467         seq = le32_to_cpu(h->seq);
2468         dname.name = (void *)h + sizeof(*h) + sizeof(u32);
2469         dname.len = msg->front.iov_len - sizeof(*h) - sizeof(u32);
2470         if (dname.len != get_unaligned_le32(h+1))
2471                 goto bad;
2472
2473         mutex_lock(&session->s_mutex);
2474         session->s_seq++;
2475
2476         /* lookup inode */
2477         inode = ceph_find_inode(sb, vino);
2478         dout("handle_lease %s, mask %d, ino %llx %p %.*s\n",
2479              ceph_lease_op_name(h->action), mask, vino.ino, inode,
2480              dname.len, dname.name);
2481         if (inode == NULL) {
2482                 dout("handle_lease no inode %llx\n", vino.ino);
2483                 goto release;
2484         }
2485         ci = ceph_inode(inode);
2486
2487         /* dentry */
2488         parent = d_find_alias(inode);
2489         if (!parent) {
2490                 dout("no parent dentry on inode %p\n", inode);
2491                 WARN_ON(1);
2492                 goto release;  /* hrm... */
2493         }
2494         dname.hash = full_name_hash(dname.name, dname.len);
2495         dentry = d_lookup(parent, &dname);
2496         dput(parent);
2497         if (!dentry)
2498                 goto release;
2499
2500         spin_lock(&dentry->d_lock);
2501         di = ceph_dentry(dentry);
2502         switch (h->action) {
2503         case CEPH_MDS_LEASE_REVOKE:
2504                 if (di && di->lease_session == session) {
2505                         if (ceph_seq_cmp(di->lease_seq, seq) > 0)
2506                                 h->seq = cpu_to_le32(di->lease_seq);
2507                         __ceph_mdsc_drop_dentry_lease(dentry);
2508                 }
2509                 release = 1;
2510                 break;
2511
2512         case CEPH_MDS_LEASE_RENEW:
2513                 if (di && di->lease_session == session &&
2514                     di->lease_gen == session->s_cap_gen &&
2515                     di->lease_renew_from &&
2516                     di->lease_renew_after == 0) {
2517                         unsigned long duration =
2518                                 le32_to_cpu(h->duration_ms) * HZ / 1000;
2519
2520                         di->lease_seq = seq;
2521                         dentry->d_time = di->lease_renew_from + duration;
2522                         di->lease_renew_after = di->lease_renew_from +
2523                                 (duration >> 1);
2524                         di->lease_renew_from = 0;
2525                 }
2526                 break;
2527         }
2528         spin_unlock(&dentry->d_lock);
2529         dput(dentry);
2530
2531         if (!release)
2532                 goto out;
2533
2534 release:
2535         /* let's just reuse the same message */
2536         h->action = CEPH_MDS_LEASE_REVOKE_ACK;
2537         ceph_msg_get(msg);
2538         ceph_con_send(&session->s_con, msg);
2539
2540 out:
2541         iput(inode);
2542         mutex_unlock(&session->s_mutex);
2543         return;
2544
2545 bad:
2546         pr_err("corrupt lease message\n");
2547         ceph_msg_dump(msg);
2548 }
2549
2550 void ceph_mdsc_lease_send_msg(struct ceph_mds_session *session,
2551                               struct inode *inode,
2552                               struct dentry *dentry, char action,
2553                               u32 seq)
2554 {
2555         struct ceph_msg *msg;
2556         struct ceph_mds_lease *lease;
2557         int len = sizeof(*lease) + sizeof(u32);
2558         int dnamelen = 0;
2559
2560         dout("lease_send_msg inode %p dentry %p %s to mds%d\n",
2561              inode, dentry, ceph_lease_op_name(action), session->s_mds);
2562         dnamelen = dentry->d_name.len;
2563         len += dnamelen;
2564
2565         msg = ceph_msg_new(CEPH_MSG_CLIENT_LEASE, len, GFP_NOFS);
2566         if (!msg)
2567                 return;
2568         lease = msg->front.iov_base;
2569         lease->action = action;
2570         lease->mask = cpu_to_le16(1);
2571         lease->ino = cpu_to_le64(ceph_vino(inode).ino);
2572         lease->first = lease->last = cpu_to_le64(ceph_vino(inode).snap);
2573         lease->seq = cpu_to_le32(seq);
2574         put_unaligned_le32(dnamelen, lease + 1);
2575         memcpy((void *)(lease + 1) + 4, dentry->d_name.name, dnamelen);
2576
2577         /*
2578          * if this is a preemptive lease RELEASE, no need to
2579          * flush request stream, since the actual request will
2580          * soon follow.
2581          */
2582         msg->more_to_follow = (action == CEPH_MDS_LEASE_RELEASE);
2583
2584         ceph_con_send(&session->s_con, msg);
2585 }
2586
2587 /*
2588  * Preemptively release a lease we expect to invalidate anyway.
2589  * Pass @inode always, @dentry is optional.
2590  */
2591 void ceph_mdsc_lease_release(struct ceph_mds_client *mdsc, struct inode *inode,
2592                              struct dentry *dentry, int mask)
2593 {
2594         struct ceph_dentry_info *di;
2595         struct ceph_mds_session *session;
2596         u32 seq;
2597
2598         BUG_ON(inode == NULL);
2599         BUG_ON(dentry == NULL);
2600         BUG_ON(mask == 0);
2601
2602         /* is dentry lease valid? */
2603         spin_lock(&dentry->d_lock);
2604         di = ceph_dentry(dentry);
2605         if (!di || !di->lease_session ||
2606             di->lease_session->s_mds < 0 ||
2607             di->lease_gen != di->lease_session->s_cap_gen ||
2608             !time_before(jiffies, dentry->d_time)) {
2609                 dout("lease_release inode %p dentry %p -- "
2610                      "no lease on %d\n",
2611                      inode, dentry, mask);
2612                 spin_unlock(&dentry->d_lock);
2613                 return;
2614         }
2615
2616         /* we do have a lease on this dentry; note mds and seq */
2617         session = ceph_get_mds_session(di->lease_session);
2618         seq = di->lease_seq;
2619         __ceph_mdsc_drop_dentry_lease(dentry);
2620         spin_unlock(&dentry->d_lock);
2621
2622         dout("lease_release inode %p dentry %p mask %d to mds%d\n",
2623              inode, dentry, mask, session->s_mds);
2624         ceph_mdsc_lease_send_msg(session, inode, dentry,
2625                                  CEPH_MDS_LEASE_RELEASE, seq);
2626         ceph_put_mds_session(session);
2627 }
2628
2629 /*
2630  * drop all leases (and dentry refs) in preparation for umount
2631  */
2632 static void drop_leases(struct ceph_mds_client *mdsc)
2633 {
2634         int i;
2635
2636         dout("drop_leases\n");
2637         mutex_lock(&mdsc->mutex);
2638         for (i = 0; i < mdsc->max_sessions; i++) {
2639                 struct ceph_mds_session *s = __ceph_lookup_mds_session(mdsc, i);
2640                 if (!s)
2641                         continue;
2642                 mutex_unlock(&mdsc->mutex);
2643                 mutex_lock(&s->s_mutex);
2644                 mutex_unlock(&s->s_mutex);
2645                 ceph_put_mds_session(s);
2646                 mutex_lock(&mdsc->mutex);
2647         }
2648         mutex_unlock(&mdsc->mutex);
2649 }
2650
2651
2652
2653 /*
2654  * delayed work -- periodically trim expired leases, renew caps with mds
2655  */
2656 static void schedule_delayed(struct ceph_mds_client *mdsc)
2657 {
2658         int delay = 5;
2659         unsigned hz = round_jiffies_relative(HZ * delay);
2660         schedule_delayed_work(&mdsc->delayed_work, hz);
2661 }
2662
2663 static void delayed_work(struct work_struct *work)
2664 {
2665         int i;
2666         struct ceph_mds_client *mdsc =
2667                 container_of(work, struct ceph_mds_client, delayed_work.work);
2668         int renew_interval;
2669         int renew_caps;
2670
2671         dout("mdsc delayed_work\n");
2672         ceph_check_delayed_caps(mdsc);
2673
2674         mutex_lock(&mdsc->mutex);
2675         renew_interval = mdsc->mdsmap->m_session_timeout >> 2;
2676         renew_caps = time_after_eq(jiffies, HZ*renew_interval +
2677                                    mdsc->last_renew_caps);
2678         if (renew_caps)
2679                 mdsc->last_renew_caps = jiffies;
2680
2681         for (i = 0; i < mdsc->max_sessions; i++) {
2682                 struct ceph_mds_session *s = __ceph_lookup_mds_session(mdsc, i);
2683                 if (s == NULL)
2684                         continue;
2685                 if (s->s_state == CEPH_MDS_SESSION_CLOSING) {
2686                         dout("resending session close request for mds%d\n",
2687                              s->s_mds);
2688                         request_close_session(mdsc, s);
2689                         ceph_put_mds_session(s);
2690                         continue;
2691                 }
2692                 if (s->s_ttl && time_after(jiffies, s->s_ttl)) {
2693                         if (s->s_state == CEPH_MDS_SESSION_OPEN) {
2694                                 s->s_state = CEPH_MDS_SESSION_HUNG;
2695                                 pr_info("mds%d hung\n", s->s_mds);
2696                         }
2697                 }
2698                 if (s->s_state < CEPH_MDS_SESSION_OPEN) {
2699                         /* this mds is failed or recovering, just wait */
2700                         ceph_put_mds_session(s);
2701                         continue;
2702                 }
2703                 mutex_unlock(&mdsc->mutex);
2704
2705                 mutex_lock(&s->s_mutex);
2706                 if (renew_caps)
2707                         send_renew_caps(mdsc, s);
2708                 else
2709                         ceph_con_keepalive(&s->s_con);
2710                 ceph_add_cap_releases(mdsc, s, -1);
2711                 if (s->s_state == CEPH_MDS_SESSION_OPEN ||
2712                     s->s_state == CEPH_MDS_SESSION_HUNG)
2713                         ceph_send_cap_releases(mdsc, s);
2714                 mutex_unlock(&s->s_mutex);
2715                 ceph_put_mds_session(s);
2716
2717                 mutex_lock(&mdsc->mutex);
2718         }
2719         mutex_unlock(&mdsc->mutex);
2720
2721         schedule_delayed(mdsc);
2722 }
2723
2724
2725 int ceph_mdsc_init(struct ceph_mds_client *mdsc, struct ceph_client *client)
2726 {
2727         mdsc->client = client;
2728         mutex_init(&mdsc->mutex);
2729         mdsc->mdsmap = kzalloc(sizeof(*mdsc->mdsmap), GFP_NOFS);
2730         if (mdsc->mdsmap == NULL)
2731                 return -ENOMEM;
2732
2733         init_completion(&mdsc->safe_umount_waiters);
2734         init_completion(&mdsc->session_close_waiters);
2735         INIT_LIST_HEAD(&mdsc->waiting_for_map);
2736         mdsc->sessions = NULL;
2737         mdsc->max_sessions = 0;
2738         mdsc->stopping = 0;
2739         init_rwsem(&mdsc->snap_rwsem);
2740         mdsc->snap_realms = RB_ROOT;
2741         INIT_LIST_HEAD(&mdsc->snap_empty);
2742         spin_lock_init(&mdsc->snap_empty_lock);
2743         mdsc->last_tid = 0;
2744         mdsc->request_tree = RB_ROOT;
2745         INIT_DELAYED_WORK(&mdsc->delayed_work, delayed_work);
2746         mdsc->last_renew_caps = jiffies;
2747         INIT_LIST_HEAD(&mdsc->cap_delay_list);
2748         spin_lock_init(&mdsc->cap_delay_lock);
2749         INIT_LIST_HEAD(&mdsc->snap_flush_list);
2750         spin_lock_init(&mdsc->snap_flush_lock);
2751         mdsc->cap_flush_seq = 0;
2752         INIT_LIST_HEAD(&mdsc->cap_dirty);
2753         mdsc->num_cap_flushing = 0;
2754         spin_lock_init(&mdsc->cap_dirty_lock);
2755         init_waitqueue_head(&mdsc->cap_flushing_wq);
2756         spin_lock_init(&mdsc->dentry_lru_lock);
2757         INIT_LIST_HEAD(&mdsc->dentry_lru);
2758
2759         return 0;
2760 }
2761
2762 /*
2763  * Wait for safe replies on open mds requests.  If we time out, drop
2764  * all requests from the tree to avoid dangling dentry refs.
2765  */
2766 static void wait_requests(struct ceph_mds_client *mdsc)
2767 {
2768         struct ceph_mds_request *req;
2769         struct ceph_client *client = mdsc->client;
2770
2771         mutex_lock(&mdsc->mutex);
2772         if (__get_oldest_req(mdsc)) {
2773                 mutex_unlock(&mdsc->mutex);
2774
2775                 dout("wait_requests waiting for requests\n");
2776                 wait_for_completion_timeout(&mdsc->safe_umount_waiters,
2777                                     client->mount_args->mount_timeout * HZ);
2778
2779                 /* tear down remaining requests */
2780                 mutex_lock(&mdsc->mutex);
2781                 while ((req = __get_oldest_req(mdsc))) {
2782                         dout("wait_requests timed out on tid %llu\n",
2783                              req->r_tid);
2784                         __unregister_request(mdsc, req);
2785                 }
2786         }
2787         mutex_unlock(&mdsc->mutex);
2788         dout("wait_requests done\n");
2789 }
2790
2791 /*
2792  * called before mount is ro, and before dentries are torn down.
2793  * (hmm, does this still race with new lookups?)
2794  */
2795 void ceph_mdsc_pre_umount(struct ceph_mds_client *mdsc)
2796 {
2797         dout("pre_umount\n");
2798         mdsc->stopping = 1;
2799
2800         drop_leases(mdsc);
2801         ceph_flush_dirty_caps(mdsc);
2802         wait_requests(mdsc);
2803
2804         /*
2805          * wait for reply handlers to drop their request refs and
2806          * their inode/dcache refs
2807          */
2808         ceph_msgr_flush();
2809 }
2810
2811 /*
2812  * wait for all write mds requests to flush.
2813  */
2814 static void wait_unsafe_requests(struct ceph_mds_client *mdsc, u64 want_tid)
2815 {
2816         struct ceph_mds_request *req = NULL, *nextreq;
2817         struct rb_node *n;
2818
2819         mutex_lock(&mdsc->mutex);
2820         dout("wait_unsafe_requests want %lld\n", want_tid);
2821 restart:
2822         req = __get_oldest_req(mdsc);
2823         while (req && req->r_tid <= want_tid) {
2824                 /* find next request */
2825                 n = rb_next(&req->r_node);
2826                 if (n)
2827                         nextreq = rb_entry(n, struct ceph_mds_request, r_node);
2828                 else
2829                         nextreq = NULL;
2830                 if ((req->r_op & CEPH_MDS_OP_WRITE)) {
2831                         /* write op */
2832                         ceph_mdsc_get_request(req);
2833                         if (nextreq)
2834                                 ceph_mdsc_get_request(nextreq);
2835                         mutex_unlock(&mdsc->mutex);
2836                         dout("wait_unsafe_requests  wait on %llu (want %llu)\n",
2837                              req->r_tid, want_tid);
2838                         wait_for_completion(&req->r_safe_completion);
2839                         mutex_lock(&mdsc->mutex);
2840                         ceph_mdsc_put_request(req);
2841                         if (!nextreq)
2842                                 break;  /* next dne before, so we're done! */
2843                         if (RB_EMPTY_NODE(&nextreq->r_node)) {
2844                                 /* next request was removed from tree */
2845                                 ceph_mdsc_put_request(nextreq);
2846                                 goto restart;
2847                         }
2848                         ceph_mdsc_put_request(nextreq);  /* won't go away */
2849                 }
2850                 req = nextreq;
2851         }
2852         mutex_unlock(&mdsc->mutex);
2853         dout("wait_unsafe_requests done\n");
2854 }
2855
2856 void ceph_mdsc_sync(struct ceph_mds_client *mdsc)
2857 {
2858         u64 want_tid, want_flush;
2859
2860         if (mdsc->client->mount_state == CEPH_MOUNT_SHUTDOWN)
2861                 return;
2862
2863         dout("sync\n");
2864         mutex_lock(&mdsc->mutex);
2865         want_tid = mdsc->last_tid;
2866         want_flush = mdsc->cap_flush_seq;
2867         mutex_unlock(&mdsc->mutex);
2868         dout("sync want tid %lld flush_seq %lld\n", want_tid, want_flush);
2869
2870         ceph_flush_dirty_caps(mdsc);
2871
2872         wait_unsafe_requests(mdsc, want_tid);
2873         wait_event(mdsc->cap_flushing_wq, check_cap_flush(mdsc, want_flush));
2874 }
2875
2876
2877 /*
2878  * called after sb is ro.
2879  */
2880 void ceph_mdsc_close_sessions(struct ceph_mds_client *mdsc)
2881 {
2882         struct ceph_mds_session *session;
2883         int i;
2884         int n;
2885         struct ceph_client *client = mdsc->client;
2886         unsigned long started, timeout = client->mount_args->mount_timeout * HZ;
2887
2888         dout("close_sessions\n");
2889
2890         mutex_lock(&mdsc->mutex);
2891
2892         /* close sessions */
2893         started = jiffies;
2894         while (time_before(jiffies, started + timeout)) {
2895                 dout("closing sessions\n");
2896                 n = 0;
2897                 for (i = 0; i < mdsc->max_sessions; i++) {
2898                         session = __ceph_lookup_mds_session(mdsc, i);
2899                         if (!session)
2900                                 continue;
2901                         mutex_unlock(&mdsc->mutex);
2902                         mutex_lock(&session->s_mutex);
2903                         __close_session(mdsc, session);
2904                         mutex_unlock(&session->s_mutex);
2905                         ceph_put_mds_session(session);
2906                         mutex_lock(&mdsc->mutex);
2907                         n++;
2908                 }
2909                 if (n == 0)
2910                         break;
2911
2912                 if (client->mount_state == CEPH_MOUNT_SHUTDOWN)
2913                         break;
2914
2915                 dout("waiting for sessions to close\n");
2916                 mutex_unlock(&mdsc->mutex);
2917                 wait_for_completion_timeout(&mdsc->session_close_waiters,
2918                                             timeout);
2919                 mutex_lock(&mdsc->mutex);
2920         }
2921
2922         /* tear down remaining sessions */
2923         for (i = 0; i < mdsc->max_sessions; i++) {
2924                 if (mdsc->sessions[i]) {
2925                         session = get_session(mdsc->sessions[i]);
2926                         __unregister_session(mdsc, session);
2927                         mutex_unlock(&mdsc->mutex);
2928                         mutex_lock(&session->s_mutex);
2929                         remove_session_caps(session);
2930                         mutex_unlock(&session->s_mutex);
2931                         ceph_put_mds_session(session);
2932                         mutex_lock(&mdsc->mutex);
2933                 }
2934         }
2935
2936         WARN_ON(!list_empty(&mdsc->cap_delay_list));
2937
2938         mutex_unlock(&mdsc->mutex);
2939
2940         ceph_cleanup_empty_realms(mdsc);
2941
2942         cancel_delayed_work_sync(&mdsc->delayed_work); /* cancel timer */
2943
2944         dout("stopped\n");
2945 }
2946
2947 void ceph_mdsc_stop(struct ceph_mds_client *mdsc)
2948 {
2949         dout("stop\n");
2950         cancel_delayed_work_sync(&mdsc->delayed_work); /* cancel timer */
2951         if (mdsc->mdsmap)
2952                 ceph_mdsmap_destroy(mdsc->mdsmap);
2953         kfree(mdsc->sessions);
2954 }
2955
2956
2957 /*
2958  * handle mds map update.
2959  */
2960 void ceph_mdsc_handle_map(struct ceph_mds_client *mdsc, struct ceph_msg *msg)
2961 {
2962         u32 epoch;
2963         u32 maplen;
2964         void *p = msg->front.iov_base;
2965         void *end = p + msg->front.iov_len;
2966         struct ceph_mdsmap *newmap, *oldmap;
2967         struct ceph_fsid fsid;
2968         int err = -EINVAL;
2969
2970         ceph_decode_need(&p, end, sizeof(fsid)+2*sizeof(u32), bad);
2971         ceph_decode_copy(&p, &fsid, sizeof(fsid));
2972         if (ceph_check_fsid(mdsc->client, &fsid) < 0)
2973                 return;
2974         epoch = ceph_decode_32(&p);
2975         maplen = ceph_decode_32(&p);
2976         dout("handle_map epoch %u len %d\n", epoch, (int)maplen);
2977
2978         /* do we need it? */
2979         ceph_monc_got_mdsmap(&mdsc->client->monc, epoch);
2980         mutex_lock(&mdsc->mutex);
2981         if (mdsc->mdsmap && epoch <= mdsc->mdsmap->m_epoch) {
2982                 dout("handle_map epoch %u <= our %u\n",
2983                      epoch, mdsc->mdsmap->m_epoch);
2984                 mutex_unlock(&mdsc->mutex);
2985                 return;
2986         }
2987
2988         newmap = ceph_mdsmap_decode(&p, end);
2989         if (IS_ERR(newmap)) {
2990                 err = PTR_ERR(newmap);
2991                 goto bad_unlock;
2992         }
2993
2994         /* swap into place */
2995         if (mdsc->mdsmap) {
2996                 oldmap = mdsc->mdsmap;
2997                 mdsc->mdsmap = newmap;
2998                 check_new_map(mdsc, newmap, oldmap);
2999                 ceph_mdsmap_destroy(oldmap);
3000         } else {
3001                 mdsc->mdsmap = newmap;  /* first mds map */
3002         }
3003         mdsc->client->sb->s_maxbytes = mdsc->mdsmap->m_max_file_size;
3004
3005         __wake_requests(mdsc, &mdsc->waiting_for_map);
3006
3007         mutex_unlock(&mdsc->mutex);
3008         schedule_delayed(mdsc);
3009         return;
3010
3011 bad_unlock:
3012         mutex_unlock(&mdsc->mutex);
3013 bad:
3014         pr_err("error decoding mdsmap %d\n", err);
3015         return;
3016 }
3017
3018 static struct ceph_connection *con_get(struct ceph_connection *con)
3019 {
3020         struct ceph_mds_session *s = con->private;
3021
3022         if (get_session(s)) {
3023                 dout("mdsc con_get %p ok (%d)\n", s, atomic_read(&s->s_ref));
3024                 return con;
3025         }
3026         dout("mdsc con_get %p FAIL\n", s);
3027         return NULL;
3028 }
3029
3030 static void con_put(struct ceph_connection *con)
3031 {
3032         struct ceph_mds_session *s = con->private;
3033
3034         ceph_put_mds_session(s);
3035         dout("mdsc con_put %p (%d)\n", s, atomic_read(&s->s_ref));
3036 }
3037
3038 /*
3039  * if the client is unresponsive for long enough, the mds will kill
3040  * the session entirely.
3041  */
3042 static void peer_reset(struct ceph_connection *con)
3043 {
3044         struct ceph_mds_session *s = con->private;
3045         struct ceph_mds_client *mdsc = s->s_mdsc;
3046
3047         pr_warning("mds%d closed our session\n", s->s_mds);
3048         send_mds_reconnect(mdsc, s);
3049 }
3050
3051 static void dispatch(struct ceph_connection *con, struct ceph_msg *msg)
3052 {
3053         struct ceph_mds_session *s = con->private;
3054         struct ceph_mds_client *mdsc = s->s_mdsc;
3055         int type = le16_to_cpu(msg->hdr.type);
3056
3057         mutex_lock(&mdsc->mutex);
3058         if (__verify_registered_session(mdsc, s) < 0) {
3059                 mutex_unlock(&mdsc->mutex);
3060                 goto out;
3061         }
3062         mutex_unlock(&mdsc->mutex);
3063
3064         switch (type) {
3065         case CEPH_MSG_MDS_MAP:
3066                 ceph_mdsc_handle_map(mdsc, msg);
3067                 break;
3068         case CEPH_MSG_CLIENT_SESSION:
3069                 handle_session(s, msg);
3070                 break;
3071         case CEPH_MSG_CLIENT_REPLY:
3072                 handle_reply(s, msg);
3073                 break;
3074         case CEPH_MSG_CLIENT_REQUEST_FORWARD:
3075                 handle_forward(mdsc, s, msg);
3076                 break;
3077         case CEPH_MSG_CLIENT_CAPS:
3078                 ceph_handle_caps(s, msg);
3079                 break;
3080         case CEPH_MSG_CLIENT_SNAP:
3081                 ceph_handle_snap(mdsc, s, msg);
3082                 break;
3083         case CEPH_MSG_CLIENT_LEASE:
3084                 handle_lease(mdsc, s, msg);
3085                 break;
3086
3087         default:
3088                 pr_err("received unknown message type %d %s\n", type,
3089                        ceph_msg_type_name(type));
3090         }
3091 out:
3092         ceph_msg_put(msg);
3093 }
3094
3095 /*
3096  * authentication
3097  */
3098 static int get_authorizer(struct ceph_connection *con,
3099                           void **buf, int *len, int *proto,
3100                           void **reply_buf, int *reply_len, int force_new)
3101 {
3102         struct ceph_mds_session *s = con->private;
3103         struct ceph_mds_client *mdsc = s->s_mdsc;
3104         struct ceph_auth_client *ac = mdsc->client->monc.auth;
3105         int ret = 0;
3106
3107         if (force_new && s->s_authorizer) {
3108                 ac->ops->destroy_authorizer(ac, s->s_authorizer);
3109                 s->s_authorizer = NULL;
3110         }
3111         if (s->s_authorizer == NULL) {
3112                 if (ac->ops->create_authorizer) {
3113                         ret = ac->ops->create_authorizer(
3114                                 ac, CEPH_ENTITY_TYPE_MDS,
3115                                 &s->s_authorizer,
3116                                 &s->s_authorizer_buf,
3117                                 &s->s_authorizer_buf_len,
3118                                 &s->s_authorizer_reply_buf,
3119                                 &s->s_authorizer_reply_buf_len);
3120                         if (ret)
3121                                 return ret;
3122                 }
3123         }
3124
3125         *proto = ac->protocol;
3126         *buf = s->s_authorizer_buf;
3127         *len = s->s_authorizer_buf_len;
3128         *reply_buf = s->s_authorizer_reply_buf;
3129         *reply_len = s->s_authorizer_reply_buf_len;
3130         return 0;
3131 }
3132
3133
3134 static int verify_authorizer_reply(struct ceph_connection *con, int len)
3135 {
3136         struct ceph_mds_session *s = con->private;
3137         struct ceph_mds_client *mdsc = s->s_mdsc;
3138         struct ceph_auth_client *ac = mdsc->client->monc.auth;
3139
3140         return ac->ops->verify_authorizer_reply(ac, s->s_authorizer, len);
3141 }
3142
3143 static int invalidate_authorizer(struct ceph_connection *con)
3144 {
3145         struct ceph_mds_session *s = con->private;
3146         struct ceph_mds_client *mdsc = s->s_mdsc;
3147         struct ceph_auth_client *ac = mdsc->client->monc.auth;
3148
3149         if (ac->ops->invalidate_authorizer)
3150                 ac->ops->invalidate_authorizer(ac, CEPH_ENTITY_TYPE_MDS);
3151
3152         return ceph_monc_validate_auth(&mdsc->client->monc);
3153 }
3154
3155 static const struct ceph_connection_operations mds_con_ops = {
3156         .get = con_get,
3157         .put = con_put,
3158         .dispatch = dispatch,
3159         .get_authorizer = get_authorizer,
3160         .verify_authorizer_reply = verify_authorizer_reply,
3161         .invalidate_authorizer = invalidate_authorizer,
3162         .peer_reset = peer_reset,
3163 };
3164
3165
3166
3167
3168 /* eof */